--- OA_place: publisher OA_type: hybrid PlanS_conform: '1' _id: '21449' abstract: - lang: eng text: Three-dimensional (3D) crystals offer a route to scaling up trapped-ion systems for quantum sensing and quantum simulation applications; however, engineering coherent spin-motion couplings and effective spin-spin interactions in large crystals poses technical challenges associated with decoherence and prolonged timescales to generate appreciable entanglement. Here, we explore the possibility of speeding up these interactions in 3D crystals via parametric amplification. For this purpose, we derive a general Hamiltonian for the parametric amplification of spin-motion coupling that is broadly applicable to normal modes with motion transverse to or along the spatial extent of the crystal. Unlike in lower-dimensional crystals, we find that the ability to faithfully (uniformly) amplify the spin-spin interactions in 3D crystals depends on the physical implementation of the spin-motion coupling. We consider the light-shift gate, and the so-called phase-insensitive and phase-sensitive Mølmer-Sørensen (MS) gates, and we find that only the phase-sensitive MS gate can be faithfully amplified in general 3D crystals. We discuss a situation where nonuniform amplification can be advantageous. We also reconsider the effect of counter-rotating terms on parametric amplification and find that they are not as detrimental as previous studies suggest. acknowledgement: We thank Wenchao Ge and Allison Carter for feedback on the manuscript. We also thank Wenchao Ge for sharing the numerical simulation data that we have used in Fig. 5 of this paper. N.N. would like to thank Perimeter Institute and Boston University for support during this research. S.H. acknowledges partial support from the Institute of Science and Technology Austria and the Austrian Science Fund (FWF) DOI 10.55776/F71 for the duration of this project. This work was supported by DOE Quantum Systems Accelerator, ARO W911NF24-1-0128, and NSF JILA-PFC PHY-2317149. J.J.B. and A.M.R. acknowledge support through AFOSR Grant No. FA9550-25-1-0080. A.S. acknowledges support by the Department of Science and Technology, Govt. of India through the INSPIRE Faculty Award (DST/INSPIRE/04/2023/001486), by the Anusandhan National Research Foundation (ANRF), Govt. of India through the Prime Minister’s Early Career Research Grant (PMECRG) (ANRF/ECRG/2024/001160/PMS) and by IIT Madras through the New Faculty Initiation Grant (NFIG). article_number: '034004' article_processing_charge: Yes (via OA deal) article_type: original arxiv: 1 author: - first_name: Samarth full_name: Hawaldar, Samarth id: 221708e1-1ff6-11ee-9fa6-85146607433e last_name: Hawaldar orcid: 0000-0002-1965-4309 - first_name: N. full_name: Nikhil, N. last_name: Nikhil - first_name: Ana Maria full_name: Rey, Ana Maria last_name: Rey - first_name: John J. full_name: Bollinger, John J. last_name: Bollinger - first_name: Athreya full_name: Shankar, Athreya last_name: Shankar citation: ama: Hawaldar S, Nikhil N, Rey AM, Bollinger JJ, Shankar A. Parametric amplification of spin-motion coupling in three-dimensional trapped-ion crystals. Physical Review Applied. 2026;25(3). doi:10.1103/h1m9-h3yw apa: Hawaldar, S., Nikhil, N., Rey, A. M., Bollinger, J. J., & Shankar, A. (2026). Parametric amplification of spin-motion coupling in three-dimensional trapped-ion crystals. Physical Review Applied. American Physical Society. https://doi.org/10.1103/h1m9-h3yw chicago: Hawaldar, Samarth, N. Nikhil, Ana Maria Rey, John J. Bollinger, and Athreya Shankar. “Parametric Amplification of Spin-Motion Coupling in Three-Dimensional Trapped-Ion Crystals.” Physical Review Applied. American Physical Society, 2026. https://doi.org/10.1103/h1m9-h3yw. ieee: S. Hawaldar, N. Nikhil, A. M. Rey, J. J. Bollinger, and A. Shankar, “Parametric amplification of spin-motion coupling in three-dimensional trapped-ion crystals,” Physical Review Applied, vol. 25, no. 3. American Physical Society, 2026. ista: Hawaldar S, Nikhil N, Rey AM, Bollinger JJ, Shankar A. 2026. Parametric amplification of spin-motion coupling in three-dimensional trapped-ion crystals. Physical Review Applied. 25(3), 034004. mla: Hawaldar, Samarth, et al. “Parametric Amplification of Spin-Motion Coupling in Three-Dimensional Trapped-Ion Crystals.” Physical Review Applied, vol. 25, no. 3, 034004, American Physical Society, 2026, doi:10.1103/h1m9-h3yw. short: S. Hawaldar, N. Nikhil, A.M. Rey, J.J. Bollinger, A. Shankar, Physical Review Applied 25 (2026). corr_author: '1' date_created: 2026-03-15T23:01:35Z date_published: 2026-03-01T00:00:00Z date_updated: 2026-04-14T09:04:08Z day: '01' ddc: - '530' department: - _id: JoFi - _id: GradSch doi: 10.1103/h1m9-h3yw external_id: arxiv: - '2507.16741' file: - access_level: open_access checksum: f0dc6a50222b778fd75cc72a28d38689 content_type: application/pdf creator: dernst date_created: 2026-03-16T09:24:53Z date_updated: 2026-03-16T09:24:53Z file_id: '21456' file_name: 2026_PhysicalReviewApplied_Hawaldar.pdf file_size: 1421954 relation: main_file success: 1 file_date_updated: 2026-03-16T09:24:53Z has_accepted_license: '1' intvolume: ' 25' issue: '3' language: - iso: eng month: '03' oa: 1 oa_version: Published Version project: - _id: bdb108fd-d553-11ed-ba76-83dc74a9864f grant_number: F07105 name: QUANTUM INFORMATION SYSTEMS BEYOND CLASSICAL CAPABILITIES / P5- Integration of Superconducting Quantum Circuits publication: Physical Review Applied publication_identifier: eissn: - 2331-7019 publication_status: published publisher: American Physical Society quality_controlled: '1' scopus_import: '1' status: public title: Parametric amplification of spin-motion coupling in three-dimensional trapped-ion crystals tmp: image: /images/cc_by.png legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0) short: CC BY (4.0) type: journal_article user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87 volume: 25 year: '2026' ... --- DOAJ_listed: '1' OA_place: publisher OA_type: gold PlanS_conform: '1' _id: '21747' abstract: - lang: eng text: Entanglement does not always require one particle per party. It was predicted some 30 years ago that a single photon traversing a beam splitter could violate a Bell inequality. Although initially debated, single-photon nonlocality was eventually demonstrated via homodyne measurements. Here, we present an alternate realization that avoids the complexity of homodyne measurements and potential loopholes in their implementation. We violate a Bell inequality by performing joint measurements on two copies of the same single-photon entangled state, where one photon acts as a phase reference for the other, making it self-referential. We observe CHSH parameters of 2.71 = 0.09 and 2.23 = 0.07, depending on the joint measurements implemented. This offers a perspective on single-photon nonlocality and a more accessible experimental route, potentially applicable to general mode-entangled states in diverse platforms. acknowledgement: European Union ERC (101071779 (GRAVITES)); European Union Horizon 2020 Research and Innovation Programme (899368 (EPIQUS)); European Union Horizon 2020 Research and Innovation Programme Marie Sklodowska-Curie (956071 (AppQInfo)); European Union HORIZON Europe Research and Innovation Programme (101135288 (EPIQUE)); FWF Austrian Science Fund (10.55776/COE1 (Quantum Science Austria), 10.55776/F71 (BeyondC), 10.55776/FG5 (Research Group 5)); United States Air Force Office of Scientific Research (FA9550-21-1-0355 (Q-Trust), FA8655-23-1-7063 (TIQI)). article_processing_charge: Yes article_type: original arxiv: 1 author: - first_name: Daniel full_name: Kun, Daniel last_name: Kun - first_name: Karl T full_name: Strömberg, Karl T id: 68011cd2-da32-11ee-a930-b2774c7aba5f last_name: Strömberg - first_name: Borivoje full_name: Dakić, Borivoje last_name: Dakić - first_name: Philip full_name: Walther, Philip last_name: Walther - first_name: Lee A. full_name: Rozema, Lee A. last_name: Rozema citation: ama: Kun D, Strömberg KT, Dakić B, Walther P, Rozema LA. Testing single-photon entanglement using self-referential measurements. Optica. 2026;13(4):745-751. doi:10.1364/OPTICA.586172 apa: Kun, D., Strömberg, K. T., Dakić, B., Walther, P., & Rozema, L. A. (2026). Testing single-photon entanglement using self-referential measurements. Optica. Optica Publishing Group. https://doi.org/10.1364/OPTICA.586172 chicago: Kun, Daniel, Karl T Strömberg, Borivoje Dakić, Philip Walther, and Lee A. Rozema. “Testing Single-Photon Entanglement Using Self-Referential Measurements.” Optica. Optica Publishing Group, 2026. https://doi.org/10.1364/OPTICA.586172. ieee: D. Kun, K. T. Strömberg, B. Dakić, P. Walther, and L. A. Rozema, “Testing single-photon entanglement using self-referential measurements,” Optica, vol. 13, no. 4. Optica Publishing Group, pp. 745–751, 2026. ista: Kun D, Strömberg KT, Dakić B, Walther P, Rozema LA. 2026. Testing single-photon entanglement using self-referential measurements. Optica. 13(4), 745–751. mla: Kun, Daniel, et al. “Testing Single-Photon Entanglement Using Self-Referential Measurements.” Optica, vol. 13, no. 4, Optica Publishing Group, 2026, pp. 745–51, doi:10.1364/OPTICA.586172. short: D. Kun, K.T. Strömberg, B. Dakić, P. Walther, L.A. Rozema, Optica 13 (2026) 745–751. date_created: 2026-04-19T22:07:44Z date_published: 2026-04-20T00:00:00Z date_updated: 2026-05-05T12:05:47Z day: '20' ddc: - '530' department: - _id: OnHo doi: 10.1364/OPTICA.586172 external_id: arxiv: - '2511.21819' file: - access_level: open_access checksum: f6e62a93f274e0c07197bf4e457eff31 content_type: application/pdf creator: dernst date_created: 2026-05-05T12:01:08Z date_updated: 2026-05-05T12:01:08Z file_id: '21799' file_name: 2026_Optica_Kun.pdf file_size: 858539 relation: main_file success: 1 file_date_updated: 2026-05-05T12:01:08Z has_accepted_license: '1' intvolume: ' 13' issue: '4' language: - iso: eng month: '04' oa: 1 oa_version: Published Version page: 745-751 project: - _id: bdb108fd-d553-11ed-ba76-83dc74a9864f grant_number: F07105 name: QUANTUM INFORMATION SYSTEMS BEYOND CLASSICAL CAPABILITIES / P5- Integration of Superconducting Quantum Circuits publication: Optica publication_identifier: eissn: - 2334-2536 publication_status: published publisher: Optica Publishing Group quality_controlled: '1' scopus_import: '1' status: public title: Testing single-photon entanglement using self-referential measurements tmp: image: /images/cc_by.png legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0) short: CC BY (4.0) type: journal_article user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87 volume: 13 year: '2026' ... --- OA_place: publisher _id: '20371' abstract: - lang: eng text: "Quantum mechanics reveals a world that defies classical determinism, where uncertainty, superposition, and fluctuations are fundamental aspects. Engineering devices that harness these quantum features requires not only precision, but also a deep understanding of how they interact with their surrounding environment. Superconducting circuits, which exploit\r\nmacroscopic quantum coherence in low-loss superconducting materials, provide a scalable platform for implementing such systems. Among the critical elements in these circuits, superinductors—high-impedance, dissipation-free inductive components—play a central role by suppressing charge fluctuations. They allow quantum states to be delocalized in phase space, protect qubits from environmental noise, and facilitate access to phenomena such as dual Josephson physics and ultra-strong coupling regimes. \r\nThis thesis explores two complementary implementations of high-impedance circuits: geometric superinductors, demonstrating that high impedance can be achieved beyond kinetic inductance,\r\nand Josephson junction chains, used to investigate both microwave mode properties and DC transport across the superconductor-to-insulator transition. \r\nPart I addresses geometric superinductors. Contrary to the common belief that high-impedance superconducting circuits require kinetic inductance, we demonstrate that purely geometric designs can achieve characteristic impedance exceeding the resistance quantum. By exploiting mutual coupling between adjacent turns, coil-based inductors achieve enhanced self-inductance, creating a reliable platform for qubits and resonators. Modeling, simulation, fabrication, and\r\ncharacterization confirm that these elements behave as superinductor. With low loss, high linearity, and minimal stray capacitance, these elements are reproducible, free of uncontrolled tunneling events, and capable of strong magnetic coupling. This establishes geometric superinductors as robust, single-wave-function superconducting devices suitable for hardware protected qubits and hybrid systems.\r\nPart II presents classical numerical simulations of a Quantum Phase Slip circuit to study dual Shapiro steps. The circuit consists of an ideal Quantum Phase Slip element embedded in a resistive-inductive environment with a parasitic capacitance.\r\nPart III extends the investigation of high characteristic-impedance circuit elements to one-dimensional Josephson junction chains, which act as a quantum simulator for many-body physics and the superconductor–insulator transition. Different devices are realized on both sides of the DC phase transition, showing either a supercurrent branch or Coulomb blockade at zero bias. The effect of the crossover on microwave modes, however, remains insufficiently investigated. Studying these modes provides insight into the interplay between disorder and phase-slip events. Small differences in circuit component sizes determine which side of the transition a device falls on, making these results relevant not only for fundamental understanding but also for the design of quantum devices, emphasizing the crucial role of the\r\nelectromagnetic environment in stabilizing and controlling fragile quantum states. \r\nTogether, these results illustrate how carefully engineered high characteristic-impedance elements provide a link between macroscopic circuits and the inherently uncertain quantum world, enabling experiments that probe, control, and ultimately exploit quantum fluctuations for applications in quantum information, metrology, solid state physics and beyond.\r\n\r\n" acknowledged_ssus: - _id: NanoFab - _id: M-Shop acknowledgement: "I also gratefully acknowledge the generous support of the NOMIS Foundation Project \"Protected\r\nStates of Quantum Matter\" and the grant from the Beyond-C consortium. Their funding\r\nmade this research possible and gave me the freedom to ask ambitious questions, and try to\r\nanswer them.\r\n" alternative_title: - ISTA Thesis article_processing_charge: No author: - first_name: Andrea full_name: Trioni, Andrea id: 42F71B44-F248-11E8-B48F-1D18A9856A87 last_name: Trioni citation: ama: 'Trioni A. High-impedance quantum circuits for mesoscopic physics : Geometric superinductors and insulating Josephson Chains. 2025. doi:10.15479/AT-ISTA-20371' apa: 'Trioni, A. (2025). High-impedance quantum circuits for mesoscopic physics : Geometric superinductors and insulating Josephson Chains. Institute of Science and Technology Austria. https://doi.org/10.15479/AT-ISTA-20371' chicago: 'Trioni, Andrea. “High-Impedance Quantum Circuits for Mesoscopic Physics : Geometric Superinductors and Insulating Josephson Chains.” Institute of Science and Technology Austria, 2025. https://doi.org/10.15479/AT-ISTA-20371.' ieee: 'A. Trioni, “High-impedance quantum circuits for mesoscopic physics : Geometric superinductors and insulating Josephson Chains,” Institute of Science and Technology Austria, 2025.' ista: 'Trioni A. 2025. High-impedance quantum circuits for mesoscopic physics : Geometric superinductors and insulating Josephson Chains. Institute of Science and Technology Austria.' mla: 'Trioni, Andrea. High-Impedance Quantum Circuits for Mesoscopic Physics : Geometric Superinductors and Insulating Josephson Chains. Institute of Science and Technology Austria, 2025, doi:10.15479/AT-ISTA-20371.' short: 'A. Trioni, High-Impedance Quantum Circuits for Mesoscopic Physics : Geometric Superinductors and Insulating Josephson Chains, Institute of Science and Technology Austria, 2025.' corr_author: '1' date_created: 2025-09-23T09:57:57Z date_published: 2025-09-23T00:00:00Z date_updated: 2026-04-15T06:43:02Z day: '23' ddc: - '539' degree_awarded: PhD department: - _id: GradSch - _id: JoFi doi: 10.15479/AT-ISTA-20371 ec_funded: 1 file: - access_level: open_access checksum: 6fb925648dfa5f4384814c552ee2f099 content_type: application/pdf creator: atrioni date_created: 2025-09-25T07:15:05Z date_updated: 2025-09-25T14:25:31Z file_id: '20392' file_name: 2025_Trioni_Andrea_Thesis.pdf file_size: 22351676 relation: main_file - access_level: closed checksum: 619dc614bdfbf3999b76ac8890b2cebd content_type: application/x-zip-compressed creator: atrioni date_created: 2025-09-25T14:45:43Z date_updated: 2025-09-26T07:20:48Z file_id: '20396' file_name: 2025_Trioni_Andrea_Thesis.zip file_size: 60079009 relation: source_file file_date_updated: 2025-09-26T07:20:48Z has_accepted_license: '1' language: - iso: eng month: '09' oa: 1 oa_version: Published Version page: '202' project: - _id: eb9b30ac-77a9-11ec-83b8-871f581d53d2 name: Protected states of quantum matter - _id: bdb108fd-d553-11ed-ba76-83dc74a9864f grant_number: F07105 name: QUANTUM INFORMATION SYSTEMS BEYOND CLASSICAL CAPABILITIES / P5- Integration of Superconducting Quantum Circuits - _id: 2564DBCA-B435-11E9-9278-68D0E5697425 call_identifier: H2020 grant_number: '665385' name: International IST Doctoral Program publication_identifier: isbn: - 978-3-99078-067-1 issn: - 2663-337X publication_status: published publisher: Institute of Science and Technology Austria related_material: record: - id: '8755' relation: part_of_dissertation status: public status: public supervisor: - first_name: Johannes M full_name: Fink, Johannes M id: 4B591CBA-F248-11E8-B48F-1D18A9856A87 last_name: Fink orcid: 0000-0001-8112-028X title: 'High-impedance quantum circuits for mesoscopic physics : Geometric superinductors and insulating Josephson Chains' type: dissertation user_id: ba8df636-2132-11f1-aed0-ed93e2281fdd year: '2025' ... --- OA_place: publisher OA_type: hybrid _id: '19073' abstract: - lang: eng text: The rapid development of superconducting quantum hardware is expected to run into substantial restrictions on scalability because error correction in a cryogenic environment has stringent input–output requirements. Classical data centres rely on fibre-optic interconnects to remove similar networking bottlenecks. In the same spirit, ultracold electro-optic links have been proposed and used to generate qubit control signals, or to replace cryogenic readout electronics. So far, these approaches have suffered from either low efficiency, low bandwidth or additional noise. Here we realize radio-over-fibre qubit readout at millikelvin temperatures. We use one device to simultaneously perform upconversion and downconversion between microwave and optical frequencies and so do not require any active or passive cryogenic microwave equipment. We demonstrate all-optical single-shot readout in a circulator-free readout scheme. Importantly, we do not observe any direct radiation impact on the qubit state, despite the absence of shielding elements. This compatibility between superconducting circuits and telecom-wavelength light is not only a prerequisite to establish modular quantum networks, but it is also relevant for multiplexed readout of superconducting photon detectors and classical superconducting logic. acknowledgement: We thank F. Hassani and M. Zemlicka for assistance with qubit design and high-power readout, respectively, and P. Winkel and I. Pop at Karlsruhe Institute of Technology for providing the JPA. This work was supported by the European Research Council under grant nos. 758053 (ERC StG QUNNECT) and 101089099 (ERC CoG cQEO), and the European Union’s Horizon 2020 research and innovation program under grant no. 899354 (FETopen SuperQuLAN). This research was funded in whole, or in part, by the Austrian Science Fund (FWF) DOI 10.55776/F71. L.Q. acknowledges generous support from the ISTFELLOW programme and G.A. is the recipient of a DOC fellowship of the Austrian Academy of Sciences at IST Austria. Open access funding provided by Institute of Science and Technology (IST Austria). article_number: '9470' article_processing_charge: Yes (via OA deal) article_type: original author: - first_name: Georg M full_name: Arnold, Georg M id: 3770C838-F248-11E8-B48F-1D18A9856A87 last_name: Arnold orcid: 0000-0003-1397-7876 - first_name: Thomas full_name: Werner, Thomas id: 1fcd8497-dba3-11ea-a45e-c6fbd715f7c7 last_name: Werner orcid: 0009-0001-2346-5236 - first_name: Rishabh full_name: Sahu, Rishabh id: 47D26E34-F248-11E8-B48F-1D18A9856A87 last_name: Sahu orcid: 0000-0001-6264-2162 - first_name: Lucky full_name: Kapoor, Lucky id: 84b9700b-15b2-11ec-abd3-831089e67615 last_name: Kapoor orcid: 0000-0001-8319-2148 - first_name: Liu full_name: Qiu, Liu id: 45e99c0d-1eb1-11eb-9b96-ed8ab2983cac last_name: Qiu orcid: 0000-0003-4345-4267 - first_name: Johannes M full_name: Fink, Johannes M id: 4B591CBA-F248-11E8-B48F-1D18A9856A87 last_name: Fink orcid: 0000-0001-8112-028X citation: ama: Arnold GM, Werner T, Sahu R, Kapoor L, Qiu L, Fink JM. All-optical superconducting qubit readout. Nature Physics. 2025;21. doi:10.1038/s41567-024-02741-4 apa: Arnold, G. M., Werner, T., Sahu, R., Kapoor, L., Qiu, L., & Fink, J. M. (2025). All-optical superconducting qubit readout. Nature Physics. Springer Nature. https://doi.org/10.1038/s41567-024-02741-4 chicago: Arnold, Georg M, Thomas Werner, Rishabh Sahu, Lucky Kapoor, Liu Qiu, and Johannes M Fink. “All-Optical Superconducting Qubit Readout.” Nature Physics. Springer Nature, 2025. https://doi.org/10.1038/s41567-024-02741-4. ieee: G. M. Arnold, T. Werner, R. Sahu, L. Kapoor, L. Qiu, and J. M. Fink, “All-optical superconducting qubit readout,” Nature Physics, vol. 21. Springer Nature, 2025. ista: Arnold GM, Werner T, Sahu R, Kapoor L, Qiu L, Fink JM. 2025. All-optical superconducting qubit readout. Nature Physics. 21, 9470. mla: Arnold, Georg M., et al. “All-Optical Superconducting Qubit Readout.” Nature Physics, vol. 21, 9470, Springer Nature, 2025, doi:10.1038/s41567-024-02741-4. short: G.M. Arnold, T. Werner, R. Sahu, L. Kapoor, L. Qiu, J.M. Fink, Nature Physics 21 (2025). corr_author: '1' date_created: 2025-02-23T23:01:57Z date_published: 2025-03-01T00:00:00Z date_updated: 2026-05-15T15:54:30Z day: '01' ddc: - '530' department: - _id: JoFi doi: 10.1038/s41567-024-02741-4 ec_funded: 1 external_id: isi: - '001417760400001' pmid: - '40093969' file: - access_level: open_access checksum: ab7469aca9e2e068eb78e5c5c1efaf7d content_type: application/pdf creator: dernst date_created: 2025-04-16T08:09:43Z date_updated: 2025-04-16T08:09:43Z file_id: '19572' file_name: 2025_NaturePhysics_Arnold.pdf file_size: 3396595 relation: main_file success: 1 file_date_updated: 2025-04-16T08:09:43Z has_accepted_license: '1' intvolume: ' 21' isi: 1 language: - iso: eng month: '03' oa: 1 oa_version: Published Version pmid: 1 project: - _id: 26336814-B435-11E9-9278-68D0E5697425 call_identifier: H2020 grant_number: '758053' name: A Fiber Optic Transceiver for Superconducting Qubits - _id: bdadfa0d-d553-11ed-ba76-fb85edbd456a grant_number: '101089099' name: 'Cavity Quantum Electro Optics: Microwave photonics with nonclassical states' - _id: 9B868D20-BA93-11EA-9121-9846C619BF3A call_identifier: H2020 grant_number: '899354' name: Quantum Local Area Networks with Superconducting Qubits - _id: 2671EB66-B435-11E9-9278-68D0E5697425 name: Coherent on-chip conversion of superconducting qubit signals from microwaves to optical frequencies - _id: bdb108fd-d553-11ed-ba76-83dc74a9864f grant_number: F07105 name: QUANTUM INFORMATION SYSTEMS BEYOND CLASSICAL CAPABILITIES / P5- Integration of Superconducting Quantum Circuits publication: Nature Physics publication_identifier: eissn: - 1745-2481 issn: - 1745-2473 publication_status: published publisher: Springer Nature quality_controlled: '1' related_material: link: - description: News on ISTA Website relation: press_release url: https://ista.ac.at/en/news/when-qubits-learn-the-language-of-fiberoptics/ record: - id: '18953' relation: earlier_version status: public - id: '21863' relation: dissertation_contains status: for_moderation scopus_import: '1' status: public title: All-optical superconducting qubit readout tmp: image: /images/cc_by.png legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0) short: CC BY (4.0) type: journal_article user_id: ba8df636-2132-11f1-aed0-ed93e2281fdd volume: 21 year: '2025' ... --- OA_place: publisher _id: '18871' abstract: - lang: eng text: "\"Can we do this with a new type of computer - a quantum computer?\". This famous\r\nquotation of the brilliant Richard Feynman within a conference talk on \"Simulating physics\r\nwith computers.” is often reverently praised as the origin of the field of quantum computing.\r\nThe idea was to use quantum mechanical systems itself to simulate \"Nature\", which is\r\ninherently quantum mechanical. Now, 43 years later, the theoretical framework of how such\r\na computer can operate has been developed. Two main important concepts for a potential\r\nquantum supremacy, superposition and entanglement, have been exploited to design quantum\r\nalgorithms to significantly speed up certain tasks. Yet, the specific hardware implementation\r\nis still far from being certain, in fact the race between the most promising platforms such as\r\nsuperconducting qubits, bosonic codes, cold atoms, trapped ions, optical computing as well\r\nas spin qubits has recently intensified. If one also includes the most mature applications of\r\nquantum communication technologies, secure quantum key distribution and quantum random\r\nnumber generators, as part of a quantum information technology ecosystem, we are confronted\r\nwith a plethora of different materials, concepts, and also operation frequencies. While\r\nsuperconducting qubits, bosonic codes and spin qubits work in the regime of approximately 5\r\nGHz and are controlled by electrical fields, trapped ions, cold atoms, and optical quantum\r\ncomputing operate with light in the infrared or visible range.\r\nConsequently, a quantum frequency converter or microwave-optic transducer is required\r\nto interface the different frequency domains or establish a long-range network connection\r\nwith suitable telecom fibers. In fact, the combination of different frequency regimes is also\r\nan essential part in our classical modern communication network, where computations are\r\nperformed in electrical circuits and the information exchange over longer distances happens\r\nvia optical fibers. However, the specific challenges specific to building a quantum computer,\r\nalso apply to the development of such a quantum frequency transducer: 1) As we deal with\r\nsingle excitations as the carrier of information, i.e. the smallest possible quantity, the signal\r\ncan easily be corrupted by other noise sources which needs to be avoided by all means. This\r\nis also the reason why microwave quantum computers operate at temperature environments\r\nclose to zero temperature (< 0.1 Kelvin) to avoid corruption by thermal noise. 2) The\r\nfrequency interface generally needs to preserve the phase of the signal as an essential part\r\nof the quantum state. And 3) Quantum signals cannot be copied which would be a typical\r\nstrategy to account for errors in classical computers. And finally, there is a challenge specific to\r\nmicrowave-optic transducers: While quantum computers are operating in one specific frequency\r\ndomain, microwave-optic transducers combine microwave and optical fields in one device.\r\nThis results in the particular challenge that high-energy optical radiation, which is usually\r\nwell-shielded from superconducting microwave quantum processors, are now an essential part\r\nof the device. The concomitant optical radiation in the operating transducer will inevitably\r\nhave a detrimental effect on the superconducting microwave components. Together with the\r\nrequirement of minimal background noise for quantum-limited operation as described above,\r\nv\r\nheating from the absorption of optical photons within the same device where single microwave\r\nexcitations are processed forms a formidable challenge.\r\nThis thesis aims to address this challenge by developing microwave-optic transducers where\r\nthe impact of optical absorption on superconducting circuits in general and superconducting\r\nqubits specifically can be mitigated. In our first approach, we developed a compact device\r\nwith optimized interaction strengths between the different frequency domains. This minimizes\r\nthe optical powers used for transducer operation and thus the optical absorption heating. This\r\nwork was - to the best of our knowledge - the first comprehensive noise study, in an integrated\r\nmicrowave-optic transducer. Unfortunately, we saw that the optical absorption heating added\r\nnoise way above a single excitation. Consequently, a potential quantum signal would have\r\nbeen buried in the noise, added by the transduction.\r\nBuilding on this insight, we utilized a three-dimensional microwave-optic transducer instead\r\nof an integrated device. The larger heat capacity of the macroscopic device with a size\r\nof a few millimeters can absorb a larger fraction of the optical heating before it increases\r\nthe temperature of the device. This allowed us to interface the transducer directly with a\r\nsuperconducting qubit to readout the qubit state in a novel all-optical manner. We showed\r\nthat the microwave-optic transducer can be operated in a regime in which optical fields don’t\r\nharm the sensitive qubit. This is an important prerequisite for the operation of microwave-optic\r\ntransducers in conjunction with microwave quantum processors and brings the integration and\r\nseamless orchestration of different frequency components in a quantum network a step closer.\r\n" acknowledged_ssus: - _id: SSU - _id: M-Shop - _id: NanoFab acknowledgement: "This work was supported by the European Research Council under grant agreement no. 758053\r\n(ERC StG QUNNECT) and the European Union’s Horizon 2020 research, innovation program\r\nunder grant agreement no. 899354 (FETopen SuperQuLAN) and the Austrian Science Fund\r\n(FWF) through BeyondC (F7105). I want to acknowledge generous support from the Austrian\r\nAcademy of Sciences from a DOC [Doctoral program of the Austrian Academy of Sciences]\r\nfellowship (no. 25129).\r\n" alternative_title: - ISTA Thesis article_processing_charge: No author: - first_name: Georg M full_name: Arnold, Georg M id: 3770C838-F248-11E8-B48F-1D18A9856A87 last_name: Arnold orcid: 0000-0003-1397-7876 citation: ama: Arnold GM. Microwave-optic interconnects for superconducting circuits. 2025. doi:10.15479/at:ista:18871 apa: Arnold, G. M. (2025). Microwave-optic interconnects for superconducting circuits. Institute of Science and Technology Austria. https://doi.org/10.15479/at:ista:18871 chicago: Arnold, Georg M. “Microwave-Optic Interconnects for Superconducting Circuits.” Institute of Science and Technology Austria, 2025. https://doi.org/10.15479/at:ista:18871. ieee: G. M. Arnold, “Microwave-optic interconnects for superconducting circuits,” Institute of Science and Technology Austria, 2025. ista: Arnold GM. 2025. Microwave-optic interconnects for superconducting circuits. Institute of Science and Technology Austria. mla: Arnold, Georg M. Microwave-Optic Interconnects for Superconducting Circuits. Institute of Science and Technology Austria, 2025, doi:10.15479/at:ista:18871. short: G.M. Arnold, Microwave-Optic Interconnects for Superconducting Circuits, Institute of Science and Technology Austria, 2025. corr_author: '1' date_created: 2025-01-24T10:28:39Z date_published: 2025-01-24T00:00:00Z date_updated: 2026-04-16T12:20:43Z day: '24' ddc: - '530' degree_awarded: PhD department: - _id: JoFi - _id: GradSch doi: 10.15479/at:ista:18871 ec_funded: 1 file: - access_level: closed checksum: 71872702e8f46c275eaea44efc4d304f content_type: application/x-zip-compressed creator: cchlebak date_created: 2025-01-29T08:38:08Z date_updated: 2026-01-29T23:30:03Z embargo_to: open_access file_id: '18946' file_name: tex for upload.zip file_size: 18856130 relation: source_file - access_level: open_access checksum: dfaa06591970f4bff163705802fad56d content_type: application/pdf creator: cchlebak date_created: 2025-01-29T08:38:34Z date_updated: 2026-01-29T23:30:03Z embargo: 2026-01-29 file_id: '18947' file_name: ISTThesisGA2022_final.pdf file_size: 17344760 relation: main_file file_date_updated: 2026-01-29T23:30:03Z has_accepted_license: '1' language: - iso: eng license: https://creativecommons.org/licenses/by-nc-sa/4.0/ month: '01' oa: 1 oa_version: Published Version page: '135' project: - _id: 26336814-B435-11E9-9278-68D0E5697425 call_identifier: H2020 grant_number: '758053' name: A Fiber Optic Transceiver for Superconducting Qubits - _id: 9B868D20-BA93-11EA-9121-9846C619BF3A call_identifier: H2020 grant_number: '899354' name: Quantum Local Area Networks with Superconducting Qubits - _id: 2671EB66-B435-11E9-9278-68D0E5697425 name: Coherent on-chip conversion of superconducting qubit signals from microwaves to optical frequencies - _id: bdb108fd-d553-11ed-ba76-83dc74a9864f grant_number: F07105 name: QUANTUM INFORMATION SYSTEMS BEYOND CLASSICAL CAPABILITIES / P5- Integration of Superconducting Quantum Circuits publication_identifier: issn: - 2663-337X publication_status: published publisher: Institute of Science and Technology Austria related_material: record: - id: '6609' relation: part_of_dissertation status: public - id: '8529' relation: part_of_dissertation status: public - id: '18953' relation: part_of_dissertation status: public - id: '10924' relation: part_of_dissertation status: public - id: '9114' relation: part_of_dissertation status: public - id: '13200' relation: part_of_dissertation status: public status: public supervisor: - first_name: Johannes M full_name: Fink, Johannes M id: 4B591CBA-F248-11E8-B48F-1D18A9856A87 last_name: Fink orcid: 0000-0001-8112-028X title: Microwave-optic interconnects for superconducting circuits tmp: image: /images/cc_by_nc_sa.png legal_code_url: https://creativecommons.org/licenses/by-nc-sa/4.0/legalcode name: Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0) short: CC BY-NC-SA (4.0) type: dissertation user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87 year: '2025' ... --- OA_place: publisher _id: '19533' abstract: - lang: eng text: "This thesis explores advancements in quantum remote sensing and non-equilibrium phase\r\ntransitions in the microwave regime, with a focus on dissipative phase transitions and quantumenhanced sensing.\r\nIn the first project, I experimentally studied photon blockade breakdown as a dissipative phase\r\ntransition in a zero-dimensional cavity-qubit system. By defining an appropriate thermodynamic\r\nlimit, we demonstrated that the observed bistability is a genuine signature of a first-order\r\nphase transition in this system. This work provides insight into non-equilibrium quantum\r\ndynamics and phase transitions in driven-dissipative open quantum systems.\r\nThe second project focuses on the experimental realization of a phase-conjugate receiver for\r\nquantum illumination (QI), a quantum sensing protocol that enhances target detection in noisy\r\nenvironments using entangled light. While an ideal spontaneous parametric down-conversion\r\n(SPDC) source and receiver could, in theory, provide up to a 6 dB advantage over classical\r\nillumination, no such ideal receiver exists. Instead, we explore an experimental realization of a\r\nphase-conjugate receiver for QI in the microwave regime at millikelvin temperatures using a\r\nJosephson parametric converter (JPC) as a source of continuous-variable Gaussian entangled\r\nsignal-idler pairs, where a maximum 3 dB advantage is theoretically achievable. We investigate\r\nkey experimental limitations that constrain practical QI performance, contributing to the\r\ndevelopment of quantum-enhanced sensing.\r\nAdditionally, this thesis presents efficient digital signal processing (DSP) techniques implemented in C++ and Python in collaboration with Przemysław Zieliński and Luka Drmić. These\r\nmethods, optimized using the Intel Integrated Performance Primitives (IPP) library, have been\r\nessential in data acquisition, noise filtering, and correlation analysis across multiple research\r\nprojects. Although not real-time, these DSP techniques significantly enhance the accuracy of\r\nquantum measurements.\r\nOverall, this thesis advances quantum-enhanced sensing by establishing the thermodynamic\r\nlimit in a single transmon-cavity system and experimentally exploring a phase-conjugate receiver\r\nfor QI. These findings contribute to quantum metrology, particularly for weak signal detection\r\nand remote sensing in noisy environments.\r\n" acknowledged_ssus: - _id: ScienComp - _id: M-Shop - _id: NanoFab - _id: LifeSc - _id: SSU acknowledgement: "I acknowledge the generous financial support of the Austrian Science Fund (FWF) via BeyondC\r\n(F7105) and the European Union’s Horizon 2020 research and innovation program (FETopen\r\nQUARTET, Grant Agreement No. 862644), which made this research possible. I also extend\r\nmy sincere appreciation to the MIBA workshop and the Institute of Science and Technology\r\nAustria nanofabrication facility for their technical assistance, which was instrumental in realizing\r\nthis work." alternative_title: - ISTA Thesis article_processing_charge: No author: - first_name: Riya full_name: Sett, Riya id: 2E6D040E-F248-11E8-B48F-1D18A9856A87 last_name: Sett orcid: 0000-0001-7641-8348 citation: ama: Sett R. Quantum remote sensing and non-equilibrium phase transitions in the microwave regime. 2025. doi:10.15479/AT-ISTA-19533 apa: Sett, R. (2025). Quantum remote sensing and non-equilibrium phase transitions in the microwave regime. Institute of Science and Technology Austria. https://doi.org/10.15479/AT-ISTA-19533 chicago: Sett, Riya. “ Quantum Remote Sensing and Non-Equilibrium Phase Transitions in the Microwave Regime.” Institute of Science and Technology Austria, 2025. https://doi.org/10.15479/AT-ISTA-19533. ieee: R. Sett, “ Quantum remote sensing and non-equilibrium phase transitions in the microwave regime,” Institute of Science and Technology Austria, 2025. ista: Sett R. 2025. Quantum remote sensing and non-equilibrium phase transitions in the microwave regime. Institute of Science and Technology Austria. mla: Sett, Riya. Quantum Remote Sensing and Non-Equilibrium Phase Transitions in the Microwave Regime. Institute of Science and Technology Austria, 2025, doi:10.15479/AT-ISTA-19533. short: R. Sett, Quantum Remote Sensing and Non-Equilibrium Phase Transitions in the Microwave Regime, Institute of Science and Technology Austria, 2025. corr_author: '1' date_created: 2025-04-09T16:44:26Z date_published: 2025-04-01T00:00:00Z date_updated: 2026-04-16T12:20:42Z day: '1' ddc: - '530' degree_awarded: PhD department: - _id: GradSch - _id: JoFi doi: 10.15479/AT-ISTA-19533 ec_funded: 1 file: - access_level: open_access checksum: ba6cd2289d0141a160a14fc97df1632f content_type: application/pdf creator: rsett date_created: 2025-04-10T11:33:22Z date_updated: 2025-10-11T22:30:02Z embargo: 2025-10-11 file_id: '19538' file_name: PhD_Thesis_Riya_Sett_pdfa.pdf file_size: 4129208 relation: main_file - access_level: closed checksum: ee63a94cb8f7adf5e766903028b81ed6 content_type: application/x-zip-compressed creator: rsett date_created: 2025-04-10T11:34:08Z date_updated: 2025-10-11T22:30:02Z embargo_to: open_access file_id: '19539' file_name: PhD Thesis Riya Sett.zip file_size: 6646110 relation: source_file file_date_updated: 2025-10-11T22:30:02Z has_accepted_license: '1' keyword: - phase transition - open quantum system - phase diagram - cavity quantum electrodynamics - superconducting qubits - semiclassical physics - quantum optics - josephson junction - parametric converter - phase conjugation - quantum radar - quantum entanglement - correlation - quantum sensing language: - iso: eng month: '04' oa: 1 oa_version: Published Version page: '109' project: - _id: 237CBA6C-32DE-11EA-91FC-C7463DDC885E call_identifier: H2020 grant_number: '862644' name: Quantum readout techniques and technologies - _id: bdb108fd-d553-11ed-ba76-83dc74a9864f grant_number: F07105 name: QUANTUM INFORMATION SYSTEMS BEYOND CLASSICAL CAPABILITIES / P5- Integration of Superconducting Quantum Circuits publication_identifier: issn: - 2663-337X publication_status: published publisher: Institute of Science and Technology Austria related_material: record: - id: '18978' relation: research_data status: public - id: '19280' relation: part_of_dissertation status: public - id: '13117' relation: part_of_dissertation status: public - id: '17183' relation: part_of_dissertation status: public status: public supervisor: - first_name: Johannes M full_name: Fink, Johannes M id: 4B591CBA-F248-11E8-B48F-1D18A9856A87 last_name: Fink orcid: 0000-0001-8112-028X title: ' Quantum remote sensing and non-equilibrium phase transitions in the microwave regime' tmp: image: /images/cc_by.png legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0) short: CC BY (4.0) type: dissertation user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87 year: '2025' ... --- OA_place: publisher OA_type: hybrid _id: '19280' abstract: - lang: eng text: Recent advancements in superconducting circuits have enabled the experimental study of collective behavior of precisely controlled intermediate-scale ensembles of qubits. In this work, we demonstrate an atomic frequency comb formed by individual artificial atoms strongly coupled to a single resonator mode. We observe periodic microwave pulses that originate from a single coherent excitation dynamically interacting with the multiqubit ensemble. We show that this revival dynamics emerges as a consequence of the constructive and periodic rephasing of the five superconducting qubits forming the vacuum Rabi split comb. In the future, similar devices could be used as a memory with in situ tunable storage time or as an on-chip periodic pulse generator with nonclassical photon statistics. acknowledged_ssus: - _id: M-Shop - _id: NanoFab acknowledgement: 'The authors thank G. Arnold and R. Sahu for the discussions, L. Drmic for software development, the MIBA workshop and the ISTA nanofabrication facility for technical support, and VTT Technical Research Centre of Finland for providing us TWPAs for follow-up measurements. This work was supported by the Austrian Science Fund (FWF) [Grant DOI: 10.55776/F71] through BeyondC (F7105) and IST Austria. E. S. R. is the recipient of a DOC fellowship of the Austrian Academy of Sciences at IST Austria. J. M. F. and M. Ž. acknowledge support from the European Research Council under Grant Agreement No. 758053 (ERC StG QUNNECT) and a NOMIS foundation research grant.' article_number: '063601' article_processing_charge: Yes (via OA deal) article_type: original arxiv: 1 author: - first_name: Elena full_name: Redchenko, Elena id: 2C21D6E8-F248-11E8-B48F-1D18A9856A87 last_name: Redchenko - first_name: M. full_name: Zens, M. last_name: Zens - first_name: Martin full_name: Zemlicka, Martin id: 2DCF8DE6-F248-11E8-B48F-1D18A9856A87 last_name: Zemlicka orcid: 0009-0005-0878-3032 - first_name: Matilda full_name: Peruzzo, Matilda id: 3F920B30-F248-11E8-B48F-1D18A9856A87 last_name: Peruzzo orcid: 0000-0002-3415-4628 - first_name: Farid full_name: Hassani, Farid id: 2AED110C-F248-11E8-B48F-1D18A9856A87 last_name: Hassani orcid: 0000-0001-6937-5773 - first_name: Riya full_name: Sett, Riya id: 2E6D040E-F248-11E8-B48F-1D18A9856A87 last_name: Sett orcid: 0000-0001-7641-8348 - first_name: Przemyslaw D full_name: Zielinski, Przemyslaw D id: e198fcc4-f6e0-11ea-865d-b6a256760ee8 last_name: Zielinski - first_name: H. S. full_name: Dhar, H. S. last_name: Dhar - first_name: D. O. full_name: Krimer, D. O. last_name: Krimer - first_name: S. full_name: Rotter, S. last_name: Rotter - first_name: Johannes M full_name: Fink, Johannes M id: 4B591CBA-F248-11E8-B48F-1D18A9856A87 last_name: Fink orcid: 0000-0001-8112-028X citation: ama: Redchenko E, Zens M, Zemlicka M, et al. Observation of collapse and revival in a superconducting atomic frequency comb. Physical Review Letters. 2025;134(6). doi:10.1103/PhysRevLett.134.063601 apa: Redchenko, E., Zens, M., Zemlicka, M., Peruzzo, M., Hassani, F., Sett, R., … Fink, J. M. (2025). Observation of collapse and revival in a superconducting atomic frequency comb. Physical Review Letters. American Physical Society. https://doi.org/10.1103/PhysRevLett.134.063601 chicago: Redchenko, Elena, M. Zens, Martin Zemlicka, Matilda Peruzzo, Farid Hassani, Riya Sett, Przemyslaw D Zielinski, et al. “Observation of Collapse and Revival in a Superconducting Atomic Frequency Comb.” Physical Review Letters. American Physical Society, 2025. https://doi.org/10.1103/PhysRevLett.134.063601. ieee: E. Redchenko et al., “Observation of collapse and revival in a superconducting atomic frequency comb,” Physical Review Letters, vol. 134, no. 6. American Physical Society, 2025. ista: Redchenko E, Zens M, Zemlicka M, Peruzzo M, Hassani F, Sett R, Zielinski PD, Dhar HS, Krimer DO, Rotter S, Fink JM. 2025. Observation of collapse and revival in a superconducting atomic frequency comb. Physical Review Letters. 134(6), 063601. mla: Redchenko, Elena, et al. “Observation of Collapse and Revival in a Superconducting Atomic Frequency Comb.” Physical Review Letters, vol. 134, no. 6, 063601, American Physical Society, 2025, doi:10.1103/PhysRevLett.134.063601. short: E. Redchenko, M. Zens, M. Zemlicka, M. Peruzzo, F. Hassani, R. Sett, P.D. Zielinski, H.S. Dhar, D.O. Krimer, S. Rotter, J.M. Fink, Physical Review Letters 134 (2025). corr_author: '1' date_created: 2025-03-02T23:01:52Z date_published: 2025-02-14T00:00:00Z date_updated: 2026-05-15T22:31:23Z day: '14' ddc: - '530' department: - _id: JoFi doi: 10.1103/PhysRevLett.134.063601 ec_funded: 1 external_id: arxiv: - '2310.04200' isi: - '001454696700003' pmid: - '40021171' file: - access_level: open_access checksum: 633d6c5ddd9b805da22c5839d3d48df6 content_type: application/pdf creator: dernst date_created: 2025-03-04T10:40:50Z date_updated: 2025-03-04T10:40:50Z file_id: '19291' file_name: 2025_PhysReviewLetters_Redchenko.pdf file_size: 2080408 relation: main_file success: 1 file_date_updated: 2025-03-04T10:40:50Z has_accepted_license: '1' intvolume: ' 134' isi: 1 issue: '6' language: - iso: eng month: '02' oa: 1 oa_version: Published Version pmid: 1 project: - _id: bdb108fd-d553-11ed-ba76-83dc74a9864f grant_number: F07105 name: QUANTUM INFORMATION SYSTEMS BEYOND CLASSICAL CAPABILITIES / P5- Integration of Superconducting Quantum Circuits - _id: 26336814-B435-11E9-9278-68D0E5697425 call_identifier: H2020 grant_number: '758053' name: A Fiber Optic Transceiver for Superconducting Qubits - _id: 26B354CA-B435-11E9-9278-68D0E5697425 name: Controllable Collective States of Superconducting Qubit Ensembles publication: Physical Review Letters publication_identifier: eissn: - 1079-7114 issn: - 0031-9007 publication_status: published publisher: American Physical Society quality_controlled: '1' related_material: record: - id: '19533' relation: dissertation_contains status: public scopus_import: '1' status: public title: Observation of collapse and revival in a superconducting atomic frequency comb tmp: image: /images/cc_by.png legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0) short: CC BY (4.0) type: journal_article user_id: 317138e5-6ab7-11ef-aa6d-ffef3953e345 volume: 134 year: '2025' ... --- OA_place: publisher _id: '17133' abstract: - lang: eng text: "An ideal quantum computer relies on qubits capable of performing fast gate operations and\r\nmaintaining strong interconnections while preserving their quantum coherence. Since the\r\ninception of experimental eforts toward building a quantum computer, the community has\r\nfaced challenges in engineering such a system. Among the various methods of implementing a\r\nquantum computer, superconducting qubits have shown fast gates close to tens of nanoseconds,\r\nwith the state-of-the-art reaching a coherence of a few milliseconds. However, achieving\r\nsimultaneously long lifetimes with fast qubit operations poses an inherent paradox. Qubits\r\nwith high coherence require isolation from the environment, while fast operation necessitates\r\nstrong coupling of the qubit. This thesis approaches this issue by proposing the idea of\r\nengineering superconducting qubits capable of transitioning between operating in a protected\r\nregime, where the qubit is completely isolated from the environment, and coupling to the\r\ncommunication channels as needed. In this direction, we use the geometric superinductor to\r\nscan the parameter space of rf-SQUID devices, searching for a regime where we can take the\r\nqubit protection to its extreme.\r\n\r\nThis leads us to the inductively shunted transmon (IST) regime, characterized by EJ /EC ≫ 1\r\nand EJ /EL ≫ 1, where the circuit potential exhibits a double well with a large barrier\r\nseparating the local ground states of each quantum well. In this regime, although it is\r\nanticipated that the two quantum wells would be isolated from each other, we observe single\r\nfuxon tunneling between them. The interplay of the cavity photons and the fuxon transition\r\nforms a rich physical system, containing resonance conditions that allow the preparation of the\r\nfuxon ground or excited states. This enables us to study the relaxation rate of such transition\r\nand show that it can be as large as 3.6 hours. Dynamically controlling the barrier height\r\nbetween the two quantum wells allows for controllable coupling, which scales exponentially,\r\nfor a qubit encoded in two fuxon states.\r\nThe 0-π qubit is one of the very few known superconducting circuit types that ofers exponential\r\nprotection from both relaxation and dephasing simultaneously. However, this qubit is not\r\nexempt from the fact that such protection comes at the expense of complex readout and\r\ncontrol. In this thesis, we propose a way to controllably break the circuit symmetry, the\r\nkey reason for the protection, to momentarily restore the ability to control and manipulate\r\nthe qubit. An asymmetry in capacitances and inductances in the 0-π circuit is detrimental\r\nsince they lead to coupling of the protected state to the thermally occupied parasitic mode\r\nof the circuit. However, here we try to exploit a controlled asymmetry in Josephson energies\r\nand show that this can be used as a tunable coupler between the protected states. In the\r\nfuture, this should allow to perform gate operations by dynamically controlling the asymmetry\r\ninstead of driving the protected transition with microwave pulses. Therefore, we believe that\r\nthe proposed method can make the use of protected qubits more practical in experimental\r\nrealizations of quantum computing." acknowledged_ssus: - _id: NanoFab - _id: M-Shop alternative_title: - ISTA Thesis article_processing_charge: No author: - first_name: Farid full_name: Hassani, Farid id: 2AED110C-F248-11E8-B48F-1D18A9856A87 last_name: Hassani orcid: 0000-0001-6937-5773 citation: ama: Hassani F. Superconducting qubits capable of dynamic switching between protected and high-speed control regimes. 2024. doi:10.15479/at:ista:17133 apa: Hassani, F. (2024). Superconducting qubits capable of dynamic switching between protected and high-speed control regimes. Institute of Science and Technology Austria. https://doi.org/10.15479/at:ista:17133 chicago: Hassani, Farid. “Superconducting Qubits Capable of Dynamic Switching between Protected and High-Speed Control Regimes.” Institute of Science and Technology Austria, 2024. https://doi.org/10.15479/at:ista:17133. ieee: F. Hassani, “Superconducting qubits capable of dynamic switching between protected and high-speed control regimes,” Institute of Science and Technology Austria, 2024. ista: Hassani F. 2024. Superconducting qubits capable of dynamic switching between protected and high-speed control regimes. Institute of Science and Technology Austria. mla: Hassani, Farid. Superconducting Qubits Capable of Dynamic Switching between Protected and High-Speed Control Regimes. Institute of Science and Technology Austria, 2024, doi:10.15479/at:ista:17133. short: F. Hassani, Superconducting Qubits Capable of Dynamic Switching between Protected and High-Speed Control Regimes, Institute of Science and Technology Austria, 2024. corr_author: '1' date_created: 2024-06-11T18:20:05Z date_published: 2024-06-11T00:00:00Z date_updated: 2026-04-15T06:43:02Z day: '11' ddc: - '530' degree_awarded: PhD department: - _id: GradSch - _id: JoFi doi: 10.15479/at:ista:17133 file: - access_level: open_access checksum: 258c353d47fa37ea63ea43b1e10a34a0 content_type: application/pdf creator: fhassani date_created: 2024-06-12T07:53:19Z date_updated: 2024-06-20T11:52:22Z file_id: '17137' file_name: Thesis_main_final.pdf file_size: 28370759 relation: main_file - access_level: closed checksum: deffa5d0db88093f74812fa71520d5e1 content_type: text/x-tex creator: fhassani date_created: 2024-06-12T07:54:27Z date_updated: 2024-06-12T07:54:27Z file_id: '17138' file_name: Thesis_main.tex file_size: 445735 relation: source_file file_date_updated: 2024-06-20T11:52:22Z has_accepted_license: '1' keyword: - Quantum information - Qubits - Superconducting devices language: - iso: eng month: '06' oa: 1 oa_version: Published Version page: '161' project: - _id: 9B861AAC-BA93-11EA-9121-9846C619BF3A name: NOMIS Fellowship Program - _id: bdb108fd-d553-11ed-ba76-83dc74a9864f grant_number: F07105 name: QUANTUM INFORMATION SYSTEMS BEYOND CLASSICAL CAPABILITIES / P5- Integration of Superconducting Quantum Circuits publication_identifier: isbn: - 978-3-99078-040-4 issn: - 2663-337X publication_status: published publisher: Institute of Science and Technology Austria related_material: record: - id: '13227' relation: part_of_dissertation status: public - id: '9928' relation: part_of_dissertation status: public - id: '8755' relation: part_of_dissertation status: public status: public supervisor: - first_name: Johannes M full_name: Fink, Johannes M id: 4B591CBA-F248-11E8-B48F-1D18A9856A87 last_name: Fink orcid: 0000-0001-8112-028X title: Superconducting qubits capable of dynamic switching between protected and high-speed control regimes tmp: image: /images/cc_by_nc_sa.png legal_code_url: https://creativecommons.org/licenses/by-nc-sa/4.0/legalcode name: Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0) short: CC BY-NC-SA (4.0) type: dissertation user_id: ba8df636-2132-11f1-aed0-ed93e2281fdd year: '2024' ... --- APC_amount: 3782,54 DOAJ_listed: '1' OA_place: publisher OA_type: gold _id: '17183' abstract: - lang: eng text: "The photon blockade breakdown in a continuously driven cavity QED system has been proposed as a prime example for a first-order driven-dissipative quantum phase transition. However, the predicted scaling from a microscopic behavior—dominated by quantum fluctuations—to a macroscopic one—characterized by stable phases—and the associated exponents and phase diagram have not been observed so far. In this work we couple a single transmon qubit with a fixed coupling strength \U0001D454 to a superconducting cavity that is in situ bandwidth \U0001D705 tunable to controllably approach this thermodynamic limit. Even though the system remains microscopic, we observe its behavior becoming increasingly macroscopic as a function of \U0001D454/\U0001D705. For the highest realized \U0001D454/\U0001D705 of approximately 287, the system switches with a characteristic timescale as long as 6 s between a bright coherent state with approximately 8×103 intracavity photons and the vacuum state. This exceeds the microscopic timescales by 6 orders of magnitude and approaches the perfect hysteresis expected between two macroscopic attractors in the thermodynamic limit. These findings and interpretation are qualitatively supported by neoclassical theory and large-scale quantum-jump Monte Carlo simulations. Besides shedding more light on driven-dissipative physics in the limit of strong light-matter coupling, this system might also find applications in quantum sensing and metrology." acknowledged_ssus: - _id: M-Shop acknowledgement: This work has received funding from the Austrian Science Fund (FWF) through BeyondC (F7105) and the European Union’s Horizon 2020 research and innovation program under Grant Agreement No. 862644 (FETopen QUARTET). A.V. acknowledges support from the National Research, Development and Innovation Office of Hungary (NKFIH) within the Quantum Information National Laboratory of Hungary. The authors thank the MIBA workshop and the Institute of Science and Technology Austria nanofabrication facility for technical support. We are grateful to HUN-REN Cloud for providing us with suitable computational infrastructure for the simulations. article_number: '010327' article_processing_charge: Yes article_type: original arxiv: 1 author: - first_name: Riya full_name: Sett, Riya id: 2E6D040E-F248-11E8-B48F-1D18A9856A87 last_name: Sett orcid: 0000-0001-7641-8348 - first_name: Farid full_name: Hassani, Farid id: 2AED110C-F248-11E8-B48F-1D18A9856A87 last_name: Hassani orcid: 0000-0001-6937-5773 - first_name: Duc T full_name: Phan, Duc T id: 29C8C0B4-F248-11E8-B48F-1D18A9856A87 last_name: Phan - first_name: Shabir full_name: Barzanjeh, Shabir id: 2D25E1F6-F248-11E8-B48F-1D18A9856A87 last_name: Barzanjeh orcid: 0000-0003-0415-1423 - first_name: Andras full_name: Vukics, Andras last_name: Vukics - first_name: Johannes M full_name: Fink, Johannes M id: 4B591CBA-F248-11E8-B48F-1D18A9856A87 last_name: Fink orcid: 0000-0001-8112-028X citation: ama: Sett R, Hassani F, Phan DT, Barzanjeh S, Vukics A, Fink JM. Emergent macroscopic bistability induced by a single superconducting qubit. PRX Quantum. 2024;5(1). doi:10.1103/prxquantum.5.010327 apa: Sett, R., Hassani, F., Phan, D. T., Barzanjeh, S., Vukics, A., & Fink, J. M. (2024). Emergent macroscopic bistability induced by a single superconducting qubit. PRX Quantum. American Physical Society. https://doi.org/10.1103/prxquantum.5.010327 chicago: Sett, Riya, Farid Hassani, Duc T Phan, Shabir Barzanjeh, Andras Vukics, and Johannes M Fink. “Emergent Macroscopic Bistability Induced by a Single Superconducting Qubit.” PRX Quantum. American Physical Society, 2024. https://doi.org/10.1103/prxquantum.5.010327. ieee: R. Sett, F. Hassani, D. T. Phan, S. Barzanjeh, A. Vukics, and J. M. Fink, “Emergent macroscopic bistability induced by a single superconducting qubit,” PRX Quantum, vol. 5, no. 1. American Physical Society, 2024. ista: Sett R, Hassani F, Phan DT, Barzanjeh S, Vukics A, Fink JM. 2024. Emergent macroscopic bistability induced by a single superconducting qubit. PRX Quantum. 5(1), 010327. mla: Sett, Riya, et al. “Emergent Macroscopic Bistability Induced by a Single Superconducting Qubit.” PRX Quantum, vol. 5, no. 1, 010327, American Physical Society, 2024, doi:10.1103/prxquantum.5.010327. short: R. Sett, F. Hassani, D.T. Phan, S. Barzanjeh, A. Vukics, J.M. Fink, PRX Quantum 5 (2024). corr_author: '1' date_created: 2024-06-27T10:58:06Z date_published: 2024-02-16T00:00:00Z date_updated: 2026-05-15T22:31:23Z day: '16' ddc: - '530' department: - _id: JoFi - _id: AnHi doi: 10.1103/prxquantum.5.010327 ec_funded: 1 external_id: arxiv: - '2210.14182' isi: - '001171652500001' file: - access_level: open_access checksum: 0833880d47f74ad1deda93a1d8ffa5a7 content_type: application/pdf creator: cchlebak date_created: 2024-06-28T12:04:43Z date_updated: 2024-06-28T12:04:43Z file_id: '17185' file_name: 2024_PRXQuantum_Sett.pdf file_size: 1443351 relation: main_file success: 1 file_date_updated: 2024-06-28T12:04:43Z has_accepted_license: '1' intvolume: ' 5' isi: 1 issue: '1' language: - iso: eng month: '02' oa: 1 oa_version: Published Version project: - _id: 237CBA6C-32DE-11EA-91FC-C7463DDC885E call_identifier: H2020 grant_number: '862644' name: Quantum readout techniques and technologies - _id: 3AC91DDA-15DF-11EA-824D-93A3E7B544D1 call_identifier: FWF name: FWF Open Access Fund - _id: bdb108fd-d553-11ed-ba76-83dc74a9864f grant_number: F07105 name: QUANTUM INFORMATION SYSTEMS BEYOND CLASSICAL CAPABILITIES / P5- Integration of Superconducting Quantum Circuits publication: PRX Quantum publication_identifier: eissn: - 2691-3399 publication_status: published publisher: American Physical Society quality_controlled: '1' related_material: record: - id: '18978' relation: research_data status: public - id: '19533' relation: dissertation_contains status: public scopus_import: '1' status: public title: Emergent macroscopic bistability induced by a single superconducting qubit tmp: image: /images/cc_by.png legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0) short: CC BY (4.0) type: journal_article user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87 volume: 5 year: '2024' ... --- _id: '14517' abstract: - lang: eng text: 'State-of-the-art transmon qubits rely on large capacitors, which systematically improve their coherence due to reduced surface-loss participation. However, this approach increases both the footprint and the parasitic cross-coupling and is ultimately limited by radiation losses—a potential roadblock for scaling up quantum processors to millions of qubits. In this work we present transmon qubits with sizes as low as 36 × 39 µm2 with 100-nm-wide vacuum-gap capacitors that are micromachined from commercial silicon-on-insulator wafers and shadow evaporated with aluminum. We achieve a vacuum participation ratio up to 99.6% in an in-plane design that is compatible with standard coplanar circuits. Qubit relaxationtime measurements for small gaps with high zero-point electric field variance of up to 22 V/m reveal a double exponential decay indicating comparably strong qubit interaction with long-lived two-level systems. The exceptionally high selectivity of up to 20 dB to the superconductor-vacuum interface allows us to precisely back out the sub-single-photon dielectric loss tangent of aluminum oxide previously exposed to ambient conditions. In terms of future scaling potential, we achieve a ratio of qubit quality factor to a footprint area equal to 20 µm−2, which is comparable with the highest T1 devices relying on larger geometries, a value that could improve substantially for lower surface-loss superconductors. ' acknowledged_ssus: - _id: NanoFab acknowledgement: "This work was supported by the Austrian Science Fund (FWF) through BeyondC (F7105), the European Research Council under Grant Agreement No. 758053 (ERC StG QUNNECT) and a NOMIS foundation research grant. M.Z. was the recipient of a SAIA scholarship, E.R. of\r\na DOC fellowship of the Austrian Academy of Sciences, and M.P. of a Pöttinger scholarship at IST Austria. S.B. acknowledges support from Marie Skłodowska Curie Program No. 707438 (MSC-IF SUPEREOM). J.M.F. acknowledges support from the Horizon Europe Program HORIZON-CL4-2022-QUANTUM-01-SGA via Project No. 101113946 OpenSuperQPlus100 and the ISTA Nanofabrication Facility." article_number: '044054' article_processing_charge: No article_type: original arxiv: 1 author: - first_name: Martin full_name: Zemlicka, Martin id: 2DCF8DE6-F248-11E8-B48F-1D18A9856A87 last_name: Zemlicka orcid: 0009-0005-0878-3032 - first_name: Elena full_name: Redchenko, Elena id: 2C21D6E8-F248-11E8-B48F-1D18A9856A87 last_name: Redchenko - first_name: Matilda full_name: Peruzzo, Matilda id: 3F920B30-F248-11E8-B48F-1D18A9856A87 last_name: Peruzzo orcid: 0000-0002-3415-4628 - first_name: Farid full_name: Hassani, Farid id: 2AED110C-F248-11E8-B48F-1D18A9856A87 last_name: Hassani orcid: 0000-0001-6937-5773 - first_name: Andrea full_name: Trioni, Andrea id: 42F71B44-F248-11E8-B48F-1D18A9856A87 last_name: Trioni - first_name: Shabir full_name: Barzanjeh, Shabir id: 2D25E1F6-F248-11E8-B48F-1D18A9856A87 last_name: Barzanjeh orcid: 0000-0003-0415-1423 - first_name: Johannes M full_name: Fink, Johannes M id: 4B591CBA-F248-11E8-B48F-1D18A9856A87 last_name: Fink orcid: 0000-0001-8112-028X citation: ama: 'Zemlicka M, Redchenko E, Peruzzo M, et al. Compact vacuum-gap transmon qubits: Selective and sensitive probes for superconductor surface losses. Physical Review Applied. 2023;20(4). doi:10.1103/PhysRevApplied.20.044054' apa: 'Zemlicka, M., Redchenko, E., Peruzzo, M., Hassani, F., Trioni, A., Barzanjeh, S., & Fink, J. M. (2023). Compact vacuum-gap transmon qubits: Selective and sensitive probes for superconductor surface losses. Physical Review Applied. American Physical Society. https://doi.org/10.1103/PhysRevApplied.20.044054' chicago: 'Zemlicka, Martin, Elena Redchenko, Matilda Peruzzo, Farid Hassani, Andrea Trioni, Shabir Barzanjeh, and Johannes M Fink. “Compact Vacuum-Gap Transmon Qubits: Selective and Sensitive Probes for Superconductor Surface Losses.” Physical Review Applied. American Physical Society, 2023. https://doi.org/10.1103/PhysRevApplied.20.044054.' ieee: 'M. Zemlicka et al., “Compact vacuum-gap transmon qubits: Selective and sensitive probes for superconductor surface losses,” Physical Review Applied, vol. 20, no. 4. American Physical Society, 2023.' ista: 'Zemlicka M, Redchenko E, Peruzzo M, Hassani F, Trioni A, Barzanjeh S, Fink JM. 2023. Compact vacuum-gap transmon qubits: Selective and sensitive probes for superconductor surface losses. Physical Review Applied. 20(4), 044054.' mla: 'Zemlicka, Martin, et al. “Compact Vacuum-Gap Transmon Qubits: Selective and Sensitive Probes for Superconductor Surface Losses.” Physical Review Applied, vol. 20, no. 4, 044054, American Physical Society, 2023, doi:10.1103/PhysRevApplied.20.044054.' short: M. Zemlicka, E. Redchenko, M. Peruzzo, F. Hassani, A. Trioni, S. Barzanjeh, J.M. Fink, Physical Review Applied 20 (2023). corr_author: '1' date_created: 2023-11-12T23:00:55Z date_published: 2023-10-20T00:00:00Z date_updated: 2026-04-15T06:39:01Z day: '20' department: - _id: JoFi doi: 10.1103/PhysRevApplied.20.044054 ec_funded: 1 external_id: arxiv: - '2206.14104' isi: - '001095315600001' intvolume: ' 20' isi: 1 issue: '4' language: - iso: eng main_file_link: - open_access: '1' url: https://arxiv.org/abs/2206.14104 month: '10' oa: 1 oa_version: Preprint project: - _id: 26336814-B435-11E9-9278-68D0E5697425 call_identifier: H2020 grant_number: '758053' name: A Fiber Optic Transceiver for Superconducting Qubits - _id: eb9b30ac-77a9-11ec-83b8-871f581d53d2 name: Protected states of quantum matter - _id: 258047B6-B435-11E9-9278-68D0E5697425 call_identifier: H2020 grant_number: '707438' name: 'Microwave-to-Optical Quantum Link: Quantum Teleportation and Quantum Illumination with cavity Optomechanics' - _id: bdb7cfc1-d553-11ed-ba76-d2eaab167738 grant_number: '101080139' name: Open Superconducting Quantum Computers (OpenSuperQPlus) - _id: bdb108fd-d553-11ed-ba76-83dc74a9864f grant_number: F07105 name: QUANTUM INFORMATION SYSTEMS BEYOND CLASSICAL CAPABILITIES / P5- Integration of Superconducting Quantum Circuits publication: Physical Review Applied publication_identifier: eissn: - 2331-7019 publication_status: published publisher: American Physical Society quality_controlled: '1' related_material: record: - id: '14520' relation: research_data status: public scopus_import: '1' status: public title: 'Compact vacuum-gap transmon qubits: Selective and sensitive probes for superconductor surface losses' type: journal_article user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87 volume: 20 year: '2023' ... --- _id: '13106' abstract: - lang: eng text: Quantum entanglement is a key resource in currently developed quantum technologies. Sharing this fragile property between superconducting microwave circuits and optical or atomic systems would enable new functionalities, but this has been hindered by an energy scale mismatch of >104 and the resulting mutually imposed loss and noise. In this work, we created and verified entanglement between microwave and optical fields in a millikelvin environment. Using an optically pulsed superconducting electro-optical device, we show entanglement between propagating microwave and optical fields in the continuous variable domain. This achievement not only paves the way for entanglement between superconducting circuits and telecom wavelength light, but also has wide-ranging implications for hybrid quantum networks in the context of modularization, scaling, sensing, and cross-platform verification. acknowledgement: This work was supported by the European Research Council (grant no. 758053, ERC StG QUNNECT) and the European Union’s Horizon 2020 Research and Innovation Program (grant no. 899354, FETopen SuperQuLAN). L.Q. acknowledges generous support from the ISTFELLOW program. W.H. is the recipient of an ISTplus postdoctoral fellowship with funding from the European Union’s Horizon 2020 Research and Innovation Program (Marie Sklodowska-Curie grant no. 754411). G.A. is the recipient of a DOC fellowship of the Austrian Academy of Sciences at IST Austria. J.M.F. acknowledges support from the Austrian Science Fund (FWF) through BeyondC (grant no. F7105) and the European Union’s Horizon 2020 Research and Innovation Program (grant no. 862644, FETopen QUARTET). article_processing_charge: No article_type: original arxiv: 1 author: - first_name: Rishabh full_name: Sahu, Rishabh id: 47D26E34-F248-11E8-B48F-1D18A9856A87 last_name: Sahu orcid: 0000-0001-6264-2162 - first_name: Liu full_name: Qiu, Liu id: 45e99c0d-1eb1-11eb-9b96-ed8ab2983cac last_name: Qiu orcid: 0000-0003-4345-4267 - first_name: William J full_name: Hease, William J id: 29705398-F248-11E8-B48F-1D18A9856A87 last_name: Hease orcid: 0000-0001-9868-2166 - first_name: Georg M full_name: Arnold, Georg M id: 3770C838-F248-11E8-B48F-1D18A9856A87 last_name: Arnold orcid: 0000-0003-1397-7876 - first_name: Y. full_name: Minoguchi, Y. last_name: Minoguchi - first_name: P. full_name: Rabl, P. last_name: Rabl - first_name: Johannes M full_name: Fink, Johannes M id: 4B591CBA-F248-11E8-B48F-1D18A9856A87 last_name: Fink orcid: 0000-0001-8112-028X citation: ama: Sahu R, Qiu L, Hease WJ, et al. Entangling microwaves with light. Science. 2023;380(6646):718-721. doi:10.1126/science.adg3812 apa: Sahu, R., Qiu, L., Hease, W. J., Arnold, G. M., Minoguchi, Y., Rabl, P., & Fink, J. M. (2023). Entangling microwaves with light. Science. American Association for the Advancement of Science. https://doi.org/10.1126/science.adg3812 chicago: Sahu, Rishabh, Liu Qiu, William J Hease, Georg M Arnold, Y. Minoguchi, P. Rabl, and Johannes M Fink. “Entangling Microwaves with Light.” Science. American Association for the Advancement of Science, 2023. https://doi.org/10.1126/science.adg3812. ieee: R. Sahu et al., “Entangling microwaves with light,” Science, vol. 380, no. 6646. American Association for the Advancement of Science, pp. 718–721, 2023. ista: Sahu R, Qiu L, Hease WJ, Arnold GM, Minoguchi Y, Rabl P, Fink JM. 2023. Entangling microwaves with light. Science. 380(6646), 718–721. mla: Sahu, Rishabh, et al. “Entangling Microwaves with Light.” Science, vol. 380, no. 6646, American Association for the Advancement of Science, 2023, pp. 718–21, doi:10.1126/science.adg3812. short: R. Sahu, L. Qiu, W.J. Hease, G.M. Arnold, Y. Minoguchi, P. Rabl, J.M. Fink, Science 380 (2023) 718–721. corr_author: '1' date_created: 2023-05-31T11:39:24Z date_published: 2023-05-18T00:00:00Z date_updated: 2026-04-15T06:39:33Z day: '18' department: - _id: JoFi doi: 10.1126/science.adg3812 ec_funded: 1 external_id: arxiv: - '2301.03315' isi: - '000996515200004' pmid: - '37200415' intvolume: ' 380' isi: 1 issue: '6646' keyword: - Multidisciplinary language: - iso: eng main_file_link: - open_access: '1' url: https://doi.org/10.48550/arXiv.2301.03315 month: '05' oa: 1 oa_version: Preprint page: 718-721 pmid: 1 project: - _id: 26336814-B435-11E9-9278-68D0E5697425 call_identifier: H2020 grant_number: '758053' name: A Fiber Optic Transceiver for Superconducting Qubits - _id: 9B868D20-BA93-11EA-9121-9846C619BF3A call_identifier: H2020 grant_number: '899354' name: Quantum Local Area Networks with Superconducting Qubits - _id: 260C2330-B435-11E9-9278-68D0E5697425 call_identifier: H2020 grant_number: '754411' name: ISTplus - Postdoctoral Fellowships - _id: 237CBA6C-32DE-11EA-91FC-C7463DDC885E call_identifier: H2020 grant_number: '862644' name: Quantum readout techniques and technologies - _id: 2671EB66-B435-11E9-9278-68D0E5697425 name: Coherent on-chip conversion of superconducting qubit signals from microwaves to optical frequencies - _id: bdb108fd-d553-11ed-ba76-83dc74a9864f grant_number: F07105 name: QUANTUM INFORMATION SYSTEMS BEYOND CLASSICAL CAPABILITIES / P5- Integration of Superconducting Quantum Circuits publication: Science publication_identifier: eissn: - 1095-9203 issn: - 0036-8075 publication_status: published publisher: American Association for the Advancement of Science quality_controlled: '1' related_material: link: - description: News on ISTA Website relation: press_release url: https://ista.ac.at/en/news/wiring-up-quantum-circuits-with-light/ record: - id: '13122' relation: research_data status: public scopus_import: '1' status: public title: Entangling microwaves with light type: journal_article user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87 volume: 380 year: '2023' ... --- _id: '13227' abstract: - lang: eng text: Currently available quantum processors are dominated by noise, which severely limits their applicability and motivates the search for new physical qubit encodings. In this work, we introduce the inductively shunted transmon, a weakly flux-tunable superconducting qubit that offers charge offset protection for all levels and a 20-fold reduction in flux dispersion compared to the state-of-the-art resulting in a constant coherence over a full flux quantum. The parabolic confinement provided by the inductive shunt as well as the linearity of the geometric superinductor facilitates a high-power readout that resolves quantum jumps with a fidelity and QND-ness of >90% and without the need for a Josephson parametric amplifier. Moreover, the device reveals quantum tunneling physics between the two prepared fluxon ground states with a measured average decay time of up to 3.5 h. In the future, fast time-domain control of the transition matrix elements could offer a new path forward to also achieve full qubit control in the decay-protected fluxon basis. acknowledged_ssus: - _id: M-Shop - _id: NanoFab acknowledgement: The authors thank J. Koch for discussions and support with the scQubits python package, I. Rozhansky and A. Poddubny for important insights into photon-assisted tunneling, S. Barzanjeh and G. Arnold for theory, E. Redchenko, S. Pepic, the MIBA workshop and the IST nanofabrication facility for technical contributions, as well as L. Drmic, P. Zielinski and R. Sett for software development. We acknowledge the prompt support of Quantum Machines to implement active state preparation with their OPX+. This work was supported by a NOMIS foundation research grant (J.F.), the Austrian Science Fund (FWF) through BeyondC F7105 (J.F.) and IST Austria. article_number: '3968' article_processing_charge: No article_type: original author: - first_name: Farid full_name: Hassani, Farid id: 2AED110C-F248-11E8-B48F-1D18A9856A87 last_name: Hassani orcid: 0000-0001-6937-5773 - first_name: Matilda full_name: Peruzzo, Matilda id: 3F920B30-F248-11E8-B48F-1D18A9856A87 last_name: Peruzzo orcid: 0000-0002-3415-4628 - first_name: Lucky full_name: Kapoor, Lucky id: 84b9700b-15b2-11ec-abd3-831089e67615 last_name: Kapoor orcid: 0000-0001-8319-2148 - first_name: Andrea full_name: Trioni, Andrea id: 42F71B44-F248-11E8-B48F-1D18A9856A87 last_name: Trioni - first_name: Martin full_name: Zemlicka, Martin id: 2DCF8DE6-F248-11E8-B48F-1D18A9856A87 last_name: Zemlicka orcid: 0009-0005-0878-3032 - first_name: Johannes M full_name: Fink, Johannes M id: 4B591CBA-F248-11E8-B48F-1D18A9856A87 last_name: Fink orcid: 0000-0001-8112-028X citation: ama: Hassani F, Peruzzo M, Kapoor L, Trioni A, Zemlicka M, Fink JM. Inductively shunted transmons exhibit noise insensitive plasmon states and a fluxon decay exceeding 3 hours. Nature Communications. 2023;14. doi:10.1038/s41467-023-39656-2 apa: Hassani, F., Peruzzo, M., Kapoor, L., Trioni, A., Zemlicka, M., & Fink, J. M. (2023). Inductively shunted transmons exhibit noise insensitive plasmon states and a fluxon decay exceeding 3 hours. Nature Communications. Springer Nature. https://doi.org/10.1038/s41467-023-39656-2 chicago: Hassani, Farid, Matilda Peruzzo, Lucky Kapoor, Andrea Trioni, Martin Zemlicka, and Johannes M Fink. “Inductively Shunted Transmons Exhibit Noise Insensitive Plasmon States and a Fluxon Decay Exceeding 3 Hours.” Nature Communications. Springer Nature, 2023. https://doi.org/10.1038/s41467-023-39656-2. ieee: F. Hassani, M. Peruzzo, L. Kapoor, A. Trioni, M. Zemlicka, and J. M. Fink, “Inductively shunted transmons exhibit noise insensitive plasmon states and a fluxon decay exceeding 3 hours,” Nature Communications, vol. 14. Springer Nature, 2023. ista: Hassani F, Peruzzo M, Kapoor L, Trioni A, Zemlicka M, Fink JM. 2023. Inductively shunted transmons exhibit noise insensitive plasmon states and a fluxon decay exceeding 3 hours. Nature Communications. 14, 3968. mla: Hassani, Farid, et al. “Inductively Shunted Transmons Exhibit Noise Insensitive Plasmon States and a Fluxon Decay Exceeding 3 Hours.” Nature Communications, vol. 14, 3968, Springer Nature, 2023, doi:10.1038/s41467-023-39656-2. short: F. Hassani, M. Peruzzo, L. Kapoor, A. Trioni, M. Zemlicka, J.M. Fink, Nature Communications 14 (2023). corr_author: '1' date_created: 2023-07-16T22:01:08Z date_published: 2023-07-05T00:00:00Z date_updated: 2026-04-15T06:39:57Z day: '05' ddc: - '530' department: - _id: JoFi doi: 10.1038/s41467-023-39656-2 external_id: isi: - '001024729900009' pmid: - '37407570' file: - access_level: open_access checksum: a85773b5fe23516f60f7d5d31b55c200 content_type: application/pdf creator: dernst date_created: 2023-07-18T08:43:07Z date_updated: 2023-07-18T08:43:07Z file_id: '13248' file_name: 2023_NatureComm_Hassani.pdf file_size: 2899592 relation: main_file success: 1 file_date_updated: 2023-07-18T08:43:07Z has_accepted_license: '1' intvolume: ' 14' isi: 1 language: - iso: eng month: '07' oa: 1 oa_version: Published Version pmid: 1 project: - _id: 2622978C-B435-11E9-9278-68D0E5697425 name: Hybrid Semiconductor - Superconductor Quantum Devices - _id: bdb108fd-d553-11ed-ba76-83dc74a9864f grant_number: F07105 name: QUANTUM INFORMATION SYSTEMS BEYOND CLASSICAL CAPABILITIES / P5- Integration of Superconducting Quantum Circuits publication: Nature Communications publication_identifier: eissn: - 2041-1723 publication_status: published publisher: Springer Nature quality_controlled: '1' related_material: record: - id: '17133' relation: dissertation_contains status: public scopus_import: '1' status: public title: Inductively shunted transmons exhibit noise insensitive plasmon states and a fluxon decay exceeding 3 hours tmp: image: /images/cc_by.png legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0) short: CC BY (4.0) type: journal_article user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87 volume: 14 year: '2023' ... --- OA_place: publisher _id: '13175' abstract: - lang: eng text: "About a 100 years ago, we discovered that our universe is inherently noisy, that is, measuring any physical quantity with a precision beyond a certain point is not possible because of an omnipresent inherent noise. We call this - the quantum noise. Certain physical processes allow this quantum noise to get correlated in conjugate physical variables. These quantum correlations can be used to go beyond the potential of our inherently noisy universe and obtain a quantum advantage over the classical applications. \r\n\r\nQuantum noise being inherent also means that, at the fundamental level, the physical quantities are not well defined and therefore, objects can stay in multiple states at the same time. For example, the position of a particle not being well defined means that the particle is in multiple positions at the same time. About 4 decades ago, we started exploring the possibility of using objects which can be in multiple states at the same time to increase the dimensionality in computation. Thus, the field of quantum computing was born. We discovered that using quantum entanglement, a property closely related to quantum correlations, can be used to speed up computation of certain problems, such as factorisation of large numbers, faster than any known classical algorithm. Thus began the pursuit to make quantum computers a reality. \r\n\r\nTill date, we have explored quantum control over many physical systems including photons, spins, atoms, ions and even simple circuits made up of superconducting material. However, there persists one ubiquitous theme. The more readily a system interacts with an external field or matter, the more easily we can control it. But this also means that such a system can easily interact with a noisy environment and quickly lose its coherence. Consequently, such systems like electron spins need to be protected from the environment to ensure the longevity of their coherence. Other systems like nuclear spins are naturally protected as they do not interact easily with the environment. But, due to the same reason, it is harder to interact with such systems. \r\n\r\nAfter decades of experimentation with various systems, we are convinced that no one type of quantum system would be the best for all the quantum applications. We would need hybrid systems which are all interconnected - much like the current internet where all sorts of devices can all talk to each other - but now for quantum devices. A quantum internet. \r\n\r\nOptical photons are the best contenders to carry information for the quantum internet. They can carry quantum information cheaply and without much loss - the same reasons which has made them the backbone of our current internet. Following this direction, many systems, like trapped ions, have already demonstrated successful quantum links over a large distances using optical photons. However, some of the most promising contenders for quantum computing which are based on microwave frequencies have been left behind. This is because high energy optical photons can adversely affect fragile low-energy microwave systems. \r\n\r\nIn this thesis, we present substantial progress on this missing quantum link between microwave and optics using electrooptical nonlinearities in lithium niobate. The nonlinearities are enhanced by using resonant cavities for all the involved modes leading to observation of strong direct coupling between optical and microwave frequencies. With this strong coupling we are not only able to achieve almost 100\\% internal conversion efficiency with low added noise, thus presenting a quantum-enabled transducer, but also we are able to observe novel effects such as cooling of a microwave mode using optics. The strong coupling regime also leads to direct observation of dynamical backaction effect between microwave and optical frequencies which are studied in detail here. Finally, we also report first observation of microwave-optics entanglement in form of two-mode squeezed vacuum squeezed 0.7dB below vacuum level. \r\nWith this new bridge between microwave and optics, the microwave-based quantum technologies can finally be a part of a quantum network which is based on optical photons - putting us one step closer to a future with quantum internet. " acknowledged_ssus: - _id: M-Shop - _id: SSU - _id: NanoFab alternative_title: - ISTA Thesis article_processing_charge: No author: - first_name: Rishabh full_name: Sahu, Rishabh id: 47D26E34-F248-11E8-B48F-1D18A9856A87 last_name: Sahu orcid: 0000-0001-6264-2162 citation: ama: Sahu R. Cavity quantum electrooptics. 2023. doi:10.15479/at:ista:13175 apa: Sahu, R. (2023). Cavity quantum electrooptics. Institute of Science and Technology Austria. https://doi.org/10.15479/at:ista:13175 chicago: Sahu, Rishabh. “Cavity Quantum Electrooptics.” Institute of Science and Technology Austria, 2023. https://doi.org/10.15479/at:ista:13175. ieee: R. Sahu, “Cavity quantum electrooptics,” Institute of Science and Technology Austria, 2023. ista: Sahu R. 2023. Cavity quantum electrooptics. Institute of Science and Technology Austria. mla: Sahu, Rishabh. Cavity Quantum Electrooptics. Institute of Science and Technology Austria, 2023, doi:10.15479/at:ista:13175. short: R. Sahu, Cavity Quantum Electrooptics, Institute of Science and Technology Austria, 2023. corr_author: '1' date_created: 2023-06-30T08:07:43Z date_published: 2023-05-05T00:00:00Z date_updated: 2026-04-15T06:43:26Z day: '05' ddc: - '537' - '535' - '539' degree_awarded: PhD department: - _id: GradSch - _id: JoFi doi: 10.15479/at:ista:13175 ec_funded: 1 file: - access_level: open_access checksum: 7d03f1a5a5258ee43dfc3323dea4e08f content_type: application/pdf creator: cchlebak date_created: 2023-06-30T08:17:25Z date_updated: 2023-06-30T08:17:25Z file_id: '13176' file_name: thesis_pdfa.pdf file_size: 18688376 relation: main_file success: 1 - access_level: closed checksum: c3b45317ae58e0527533f98c202d81b7 content_type: application/x-zip-compressed creator: cchlebak date_created: 2023-07-06T11:35:15Z date_updated: 2023-07-06T11:35:15Z file_id: '13196' file_name: thesis.zip file_size: 37847025 relation: source_file file_date_updated: 2023-07-06T11:35:15Z has_accepted_license: '1' keyword: - quantum optics - electrooptics - quantum networks - quantum communication - transduction language: - iso: eng month: '05' oa: 1 oa_version: Published Version page: '202' project: - _id: 26336814-B435-11E9-9278-68D0E5697425 call_identifier: H2020 grant_number: '758053' name: A Fiber Optic Transceiver for Superconducting Qubits - _id: 9B868D20-BA93-11EA-9121-9846C619BF3A call_identifier: H2020 grant_number: '899354' name: Quantum Local Area Networks with Superconducting Qubits - _id: bdb108fd-d553-11ed-ba76-83dc74a9864f grant_number: F07105 name: QUANTUM INFORMATION SYSTEMS BEYOND CLASSICAL CAPABILITIES / P5- Integration of Superconducting Quantum Circuits publication_identifier: isbn: - 978-3-99078-030-5 issn: - 2663-337X publication_status: published publisher: Institute of Science and Technology Austria related_material: record: - id: '12900' relation: old_edition status: public - id: '10924' relation: part_of_dissertation status: public - id: '9114' relation: part_of_dissertation status: public status: public supervisor: - first_name: Johannes M full_name: Fink, Johannes M id: 4B591CBA-F248-11E8-B48F-1D18A9856A87 last_name: Fink orcid: 0000-0001-8112-028X title: Cavity quantum electrooptics tmp: image: /images/cc_by_nc_sa.png legal_code_url: https://creativecommons.org/licenses/by-nc-sa/4.0/legalcode name: Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0) short: CC BY-NC-SA (4.0) type: dissertation user_id: ba8df636-2132-11f1-aed0-ed93e2281fdd year: '2023' ... --- OA_place: publisher _id: '12900' abstract: - lang: eng text: "About a 100 years ago, we discovered that our universe is inherently noisy, that is, measuring any physical quantity with a precision beyond a certain point is not possible because of an omnipresent inherent noise. We call this - the quantum noise. Certain physical processes allow this quantum noise to get correlated in conjugate physical variables. These quantum correlations can be used to go beyond the potential of our inherently noisy universe and obtain a quantum advantage over the classical applications. \r\n\r\nQuantum noise being inherent also means that, at the fundamental level, the physical quantities are not well defined and therefore, objects can stay in multiple states at the same time. For example, the position of a particle not being well defined means that the particle is in multiple positions at the same time. About 4 decades ago, we started exploring the possibility of using objects which can be in multiple states at the same time to increase the dimensionality in computation. Thus, the field of quantum computing was born. We discovered that using quantum entanglement, a property closely related to quantum correlations, can be used to speed up computation of certain problems, such as factorisation of large numbers, faster than any known classical algorithm. Thus began the pursuit to make quantum computers a reality. \r\n\r\nTill date, we have explored quantum control over many physical systems including photons, spins, atoms, ions and even simple circuits made up of superconducting material. However, there persists one ubiquitous theme. The more readily a system interacts with an external field or matter, the more easily we can control it. But this also means that such a system can easily interact with a noisy environment and quickly lose its coherence. Consequently, such systems like electron spins need to be protected from the environment to ensure the longevity of their coherence. Other systems like nuclear spins are naturally protected as they do not interact easily with the environment. But, due to the same reason, it is harder to interact with such systems. \r\n\r\nAfter decades of experimentation with various systems, we are convinced that no one type of quantum system would be the best for all the quantum applications. We would need hybrid systems which are all interconnected - much like the current internet where all sorts of devices can all talk to each other - but now for quantum devices. A quantum internet. \r\n\r\nOptical photons are the best contenders to carry information for the quantum internet. They can carry quantum information cheaply and without much loss - the same reasons which has made them the backbone of our current internet. Following this direction, many systems, like trapped ions, have already demonstrated successful quantum links over a large distances using optical photons. However, some of the most promising contenders for quantum computing which are based on microwave frequencies have been left behind. This is because high energy optical photons can adversely affect fragile low-energy microwave systems. \r\n\r\nIn this thesis, we present substantial progress on this missing quantum link between microwave and optics using electrooptical nonlinearities in lithium niobate. The nonlinearities are enhanced by using resonant cavities for all the involved modes leading to observation of strong direct coupling between optical and microwave frequencies. With this strong coupling we are not only able to achieve almost 100\\% internal conversion efficiency with low added noise, thus presenting a quantum-enabled transducer, but also we are able to observe novel effects such as cooling of a microwave mode using optics. The strong coupling regime also leads to direct observation of dynamical backaction effect between microwave and optical frequencies which are studied in detail here. Finally, we also report first observation of microwave-optics entanglement in form of two-mode squeezed vacuum squeezed 0.7dB below vacuum level. \r\nWith this new bridge between microwave and optics, the microwave-based quantum technologies can finally be a part of a quantum network which is based on optical photons - putting us one step closer to a future with quantum internet. " acknowledged_ssus: - _id: M-Shop - _id: SSU - _id: NanoFab alternative_title: - ISTA Thesis article_processing_charge: No author: - first_name: Rishabh full_name: Sahu, Rishabh id: 47D26E34-F248-11E8-B48F-1D18A9856A87 last_name: Sahu orcid: 0000-0001-6264-2162 citation: ama: Sahu R. Cavity quantum electrooptics. 2023. doi:10.15479/at:ista:12900 apa: Sahu, R. (2023). Cavity quantum electrooptics. Institute of Science and Technology Austria. https://doi.org/10.15479/at:ista:12900 chicago: Sahu, Rishabh. “Cavity Quantum Electrooptics.” Institute of Science and Technology Austria, 2023. https://doi.org/10.15479/at:ista:12900. ieee: R. Sahu, “Cavity quantum electrooptics,” Institute of Science and Technology Austria, 2023. ista: Sahu R. 2023. Cavity quantum electrooptics. Institute of Science and Technology Austria. mla: Sahu, Rishabh. Cavity Quantum Electrooptics. Institute of Science and Technology Austria, 2023, doi:10.15479/at:ista:12900. short: R. Sahu, Cavity Quantum Electrooptics, Institute of Science and Technology Austria, 2023. corr_author: '1' date_created: 2023-05-05T11:08:50Z date_published: 2023-05-05T00:00:00Z date_updated: 2026-04-15T06:43:26Z day: '05' ddc: - '537' - '535' - '539' degree_awarded: PhD department: - _id: GradSch - _id: JoFi doi: 10.15479/at:ista:12900 ec_funded: 1 file: - access_level: closed checksum: 8cbdab9c37ee55e591092a6f66b272c4 content_type: application/x-zip-compressed creator: rsahu date_created: 2023-05-09T08:45:14Z date_updated: 2023-06-06T22:30:03Z embargo_to: open_access file_id: '12928' file_name: thesis.zip file_size: 36767177 relation: source_file - access_level: closed checksum: 439659ead46618147309be39d9dd5a8c content_type: application/pdf creator: rsahu date_created: 2023-05-09T08:51:17Z date_updated: 2023-07-06T11:37:40Z file_id: '12929' file_name: thesis_pdfa_final.pdf file_size: 17501990 relation: main_file file_date_updated: 2023-07-06T11:37:40Z has_accepted_license: '1' keyword: - quantum optics - electrooptics - quantum networks - quantum communication - transduction language: - iso: eng month: '05' oa_version: Published Version page: '190' project: - _id: 26336814-B435-11E9-9278-68D0E5697425 call_identifier: H2020 grant_number: '758053' name: A Fiber Optic Transceiver for Superconducting Qubits - _id: 9B868D20-BA93-11EA-9121-9846C619BF3A call_identifier: H2020 grant_number: '899354' name: Quantum Local Area Networks with Superconducting Qubits - _id: bdb108fd-d553-11ed-ba76-83dc74a9864f grant_number: F07105 name: QUANTUM INFORMATION SYSTEMS BEYOND CLASSICAL CAPABILITIES / P5- Integration of Superconducting Quantum Circuits publication_identifier: isbn: - 978-3-99078-030-5 issn: - 2663-337X publication_status: published publisher: Institute of Science and Technology Austria related_material: record: - id: '13175' relation: new_edition status: public - id: '10924' relation: part_of_dissertation status: public - id: '9114' relation: part_of_dissertation status: public status: public supervisor: - first_name: Johannes M full_name: Fink, Johannes M id: 4B591CBA-F248-11E8-B48F-1D18A9856A87 last_name: Fink orcid: 0000-0001-8112-028X title: Cavity quantum electrooptics tmp: image: /images/cc_by_nc_sa.png legal_code_url: https://creativecommons.org/licenses/by-nc-sa/4.0/legalcode name: Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0) short: CC BY-NC-SA (4.0) type: dissertation user_id: ba8df636-2132-11f1-aed0-ed93e2281fdd year: '2023' ... --- APC_amount: 6228 EUR DOAJ_listed: '1' OA_place: publisher OA_type: gold _id: '13200' abstract: - lang: eng text: Recent quantum technologies have established precise quantum control of various microscopic systems using electromagnetic waves. Interfaces based on cryogenic cavity electro-optic systems are particularly promising, due to the direct interaction between microwave and optical fields in the quantum regime. Quantum optical control of superconducting microwave circuits has been precluded so far due to the weak electro-optical coupling as well as quasi-particles induced by the pump laser. Here we report the coherent control of a superconducting microwave cavity using laser pulses in a multimode electro-optical device at millikelvin temperature with near-unity cooperativity. Both the stationary and instantaneous responses of the microwave and optical modes comply with the coherent electro-optical interaction, and reveal only minuscule amount of excess back-action with an unanticipated time delay. Our demonstration enables wide ranges of applications beyond quantum transductions, from squeezing and quantum non-demolition measurements of microwave fields, to entanglement generation and hybrid quantum networks. acknowledgement: This work was supported by the European Research Council under grant agreement no. 758053 (ERC StG QUNNECT), the European Union’s Horizon 2020 research and innovation program under grant agreement no. 899354 (FETopen SuperQuLAN), and the Austrian Science Fund (FWF) through BeyondC (F7105). L.Q. acknowledges generous support from the ISTFELLOW programme. W.H. is the recipient of an ISTplus postdoctoral fellowship with funding from the European Union’s Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant agreement no. 754411. G.A. is the recipient of a DOC fellowship of the Austrian Academy of Sciences at IST Austria. article_number: '3784' article_processing_charge: Yes article_type: original arxiv: 1 author: - first_name: Liu full_name: Qiu, Liu id: 45e99c0d-1eb1-11eb-9b96-ed8ab2983cac last_name: Qiu orcid: 0000-0003-4345-4267 - first_name: Rishabh full_name: Sahu, Rishabh id: 47D26E34-F248-11E8-B48F-1D18A9856A87 last_name: Sahu orcid: 0000-0001-6264-2162 - first_name: William J full_name: Hease, William J id: 29705398-F248-11E8-B48F-1D18A9856A87 last_name: Hease orcid: 0000-0001-9868-2166 - first_name: Georg M full_name: Arnold, Georg M id: 3770C838-F248-11E8-B48F-1D18A9856A87 last_name: Arnold orcid: 0000-0003-1397-7876 - first_name: Johannes M full_name: Fink, Johannes M id: 4B591CBA-F248-11E8-B48F-1D18A9856A87 last_name: Fink orcid: 0000-0001-8112-028X citation: ama: Qiu L, Sahu R, Hease WJ, Arnold GM, Fink JM. Coherent optical control of a superconducting microwave cavity via electro-optical dynamical back-action. Nature Communications. 2023;14. doi:10.1038/s41467-023-39493-3 apa: Qiu, L., Sahu, R., Hease, W. J., Arnold, G. M., & Fink, J. M. (2023). Coherent optical control of a superconducting microwave cavity via electro-optical dynamical back-action. Nature Communications. Nature Research. https://doi.org/10.1038/s41467-023-39493-3 chicago: Qiu, Liu, Rishabh Sahu, William J Hease, Georg M Arnold, and Johannes M Fink. “Coherent Optical Control of a Superconducting Microwave Cavity via Electro-Optical Dynamical Back-Action.” Nature Communications. Nature Research, 2023. https://doi.org/10.1038/s41467-023-39493-3. ieee: L. Qiu, R. Sahu, W. J. Hease, G. M. Arnold, and J. M. Fink, “Coherent optical control of a superconducting microwave cavity via electro-optical dynamical back-action,” Nature Communications, vol. 14. Nature Research, 2023. ista: Qiu L, Sahu R, Hease WJ, Arnold GM, Fink JM. 2023. Coherent optical control of a superconducting microwave cavity via electro-optical dynamical back-action. Nature Communications. 14, 3784. mla: Qiu, Liu, et al. “Coherent Optical Control of a Superconducting Microwave Cavity via Electro-Optical Dynamical Back-Action.” Nature Communications, vol. 14, 3784, Nature Research, 2023, doi:10.1038/s41467-023-39493-3. short: L. Qiu, R. Sahu, W.J. Hease, G.M. Arnold, J.M. Fink, Nature Communications 14 (2023). corr_author: '1' date_created: 2023-07-09T22:01:11Z date_published: 2023-06-24T00:00:00Z date_updated: 2026-05-15T22:31:21Z day: '24' ddc: - '000' department: - _id: JoFi doi: 10.1038/s41467-023-39493-3 ec_funded: 1 external_id: arxiv: - '2210.12443' isi: - '001018100800002' pmid: - '37355691' file: - access_level: open_access checksum: ec7ccd2c08f90d59cab302fd0d7776a4 content_type: application/pdf creator: alisjak date_created: 2023-07-10T10:10:54Z date_updated: 2023-07-10T10:10:54Z file_id: '13206' file_name: 2023_NatureComms_Qiu.pdf file_size: 1349134 relation: main_file success: 1 file_date_updated: 2023-07-10T10:10:54Z has_accepted_license: '1' intvolume: ' 14' isi: 1 language: - iso: eng month: '06' oa: 1 oa_version: Published Version pmid: 1 project: - _id: 26336814-B435-11E9-9278-68D0E5697425 call_identifier: H2020 grant_number: '758053' name: A Fiber Optic Transceiver for Superconducting Qubits - _id: 9B868D20-BA93-11EA-9121-9846C619BF3A call_identifier: H2020 grant_number: '899354' name: Quantum Local Area Networks with Superconducting Qubits - _id: bdb108fd-d553-11ed-ba76-83dc74a9864f grant_number: F07105 name: QUANTUM INFORMATION SYSTEMS BEYOND CLASSICAL CAPABILITIES / P5- Integration of Superconducting Quantum Circuits - _id: 260C2330-B435-11E9-9278-68D0E5697425 call_identifier: H2020 grant_number: '754411' name: ISTplus - Postdoctoral Fellowships - _id: 25681D80-B435-11E9-9278-68D0E5697425 call_identifier: FP7 grant_number: '291734' name: International IST Postdoc Fellowship Programme - _id: 2671EB66-B435-11E9-9278-68D0E5697425 name: Coherent on-chip conversion of superconducting qubit signals from microwaves to optical frequencies - _id: 3AC91DDA-15DF-11EA-824D-93A3E7B544D1 call_identifier: FWF name: FWF Open Access Fund publication: Nature Communications publication_identifier: eissn: - 2041-1723 publication_status: published publisher: Nature Research quality_controlled: '1' related_material: record: - id: '18871' relation: dissertation_contains status: public scopus_import: '1' status: public title: Coherent optical control of a superconducting microwave cavity via electro-optical dynamical back-action tmp: image: /images/cc_by.png legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0) short: CC BY (4.0) type: journal_article user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87 volume: 14 year: '2023' ... --- OA_place: repository _id: '18953' abstract: - lang: eng text: The rapid development of superconducting quantum hardware is expected to run into significant I/O restrictions due to the need for large-scale error correction in a cryogenic environment. Classical data centers rely on fiber-optic interconnects to remove similar networking bottlenecks and to allow for reconfigurable, software-defined infrastructures. In the same spirit, ultra-cold electro-optic links have been proposed and used to generate qubit control signals, or to replace cryogenic readout electronics. So far, the latter suffered from either low efficiency, low bandwidth and the need for additional microwave drives, or breaking of Cooper pairs and qubit states. In this work we realize electro-optic microwave photonics at millikelvin temperatures to implement a radio-over-fiber qubit readout that does not require any active or passive cryogenic microwave equipment. We demonstrate all-optical single-shot-readout by means of the Jaynes-Cummings nonlinearity in a circulator-free readout scheme. Importantly, we do not observe any direct radiation impact on the qubit state as verified with high-fidelity quantum-non-demolition measurements despite the absence of shielding elements. This compatibility between superconducting circuits and telecom wavelength light is not only a prerequisite to establish modular quantum networks, it is also relevant for multiplexed readout of superconducting photon detectors and classical superconducting logic. Moreover, this experiment showcases the potential of electro-optic radiometry in harsh environments - an electronics-free sensing principle that extends into the THz regime with applications in radio astronomy, planetary missions and earth observation. acknowledgement: "We thank F. Hassani and M. Zemlicka for assistance\r\nwith qubit design and high power readout respectively,\r\nand P. Winkel and I. Pop at KIT for providing the JPA.\r\nThis work was supported by the European Research\r\nCouncil under grant agreement no. 758053 (ERC StG\r\nQUNNECT) and no. 101089099 (ERC CoG cQEO), the\r\nEuropean Union’s Horizon 2020 research and innovation\r\nprogram under grant agreement no. 899354 (FETopen\r\nSuperQuLAN) and the Austrian Science Fund (FWF)\r\nthrough BeyondC (grant no. F7105). L.Q. acknowledges\r\ngenerous support from the ISTFELLOW programme\r\nand G.A. is the recipient of a DOC fellowship of the\r\nAustrian Academy of Sciences at IST Austria." article_processing_charge: No arxiv: 1 author: - first_name: Georg M full_name: Arnold, Georg M id: 3770C838-F248-11E8-B48F-1D18A9856A87 last_name: Arnold orcid: 0000-0003-1397-7876 - first_name: Thomas full_name: Werner, Thomas id: 1fcd8497-dba3-11ea-a45e-c6fbd715f7c7 last_name: Werner orcid: 0009-0001-2346-5236 - first_name: Rishabh full_name: Sahu, Rishabh id: 47D26E34-F248-11E8-B48F-1D18A9856A87 last_name: Sahu orcid: 0000-0001-6264-2162 - first_name: Lucky full_name: Kapoor, Lucky id: 84b9700b-15b2-11ec-abd3-831089e67615 last_name: Kapoor orcid: 0000-0001-8319-2148 - first_name: Liu full_name: Qiu, Liu id: 45e99c0d-1eb1-11eb-9b96-ed8ab2983cac last_name: Qiu orcid: 0000-0003-4345-4267 - first_name: Johannes M full_name: Fink, Johannes M id: 4B591CBA-F248-11E8-B48F-1D18A9856A87 last_name: Fink orcid: 0000-0001-8112-028X citation: ama: Arnold GM, Werner T, Sahu R, Kapoor L, Qiu L, Fink JM. All-optical single-shot readout of a superconducting qubit. arXiv. doi:10.48550/ARXIV.2310.16817 apa: Arnold, G. M., Werner, T., Sahu, R., Kapoor, L., Qiu, L., & Fink, J. M. (n.d.). All-optical single-shot readout of a superconducting qubit. arXiv. https://doi.org/10.48550/ARXIV.2310.16817 chicago: Arnold, Georg M, Thomas Werner, Rishabh Sahu, Lucky Kapoor, Liu Qiu, and Johannes M Fink. “All-Optical Single-Shot Readout of a Superconducting Qubit.” ArXiv, n.d. https://doi.org/10.48550/ARXIV.2310.16817. ieee: G. M. Arnold, T. Werner, R. Sahu, L. Kapoor, L. Qiu, and J. M. Fink, “All-optical single-shot readout of a superconducting qubit,” arXiv. . ista: Arnold GM, Werner T, Sahu R, Kapoor L, Qiu L, Fink JM. All-optical single-shot readout of a superconducting qubit. arXiv, 10.48550/ARXIV.2310.16817. mla: Arnold, Georg M., et al. “All-Optical Single-Shot Readout of a Superconducting Qubit.” ArXiv, doi:10.48550/ARXIV.2310.16817. short: G.M. Arnold, T. Werner, R. Sahu, L. Kapoor, L. Qiu, J.M. Fink, ArXiv (n.d.). corr_author: '1' date_created: 2025-01-29T11:11:34Z date_published: 2023-10-25T00:00:00Z date_updated: 2026-05-15T22:31:21Z day: '25' department: - _id: JoFi doi: 10.48550/ARXIV.2310.16817 ec_funded: 1 external_id: arxiv: - '2310.16817' language: - iso: eng main_file_link: - open_access: '1' url: https://doi.org/10.48550/arXiv.2310.16817 month: '10' oa: 1 oa_version: Preprint project: - _id: 26336814-B435-11E9-9278-68D0E5697425 call_identifier: H2020 grant_number: '758053' name: A Fiber Optic Transceiver for Superconducting Qubits - _id: bdadfa0d-d553-11ed-ba76-fb85edbd456a grant_number: '101089099' name: 'Cavity Quantum Electro Optics: Microwave photonics with nonclassical states' - _id: 9B868D20-BA93-11EA-9121-9846C619BF3A call_identifier: H2020 grant_number: '899354' name: Quantum Local Area Networks with Superconducting Qubits - _id: 2671EB66-B435-11E9-9278-68D0E5697425 name: Coherent on-chip conversion of superconducting qubit signals from microwaves to optical frequencies - _id: bdb108fd-d553-11ed-ba76-83dc74a9864f grant_number: F07105 name: QUANTUM INFORMATION SYSTEMS BEYOND CLASSICAL CAPABILITIES / P5- Integration of Superconducting Quantum Circuits publication: arXiv publication_status: draft related_material: record: - id: '19073' relation: later_version status: public - id: '18871' relation: dissertation_contains status: public status: public title: All-optical single-shot readout of a superconducting qubit tmp: image: /images/cc_by.png legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0) short: CC BY (4.0) type: preprint user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87 year: '2023' ... --- _id: '13117' abstract: - lang: eng text: The ability to control the direction of scattered light is crucial to provide flexibility and scalability for a wide range of on-chip applications, such as integrated photonics, quantum information processing, and nonlinear optics. Tunable directionality can be achieved by applying external magnetic fields that modify optical selection rules, by using nonlinear effects, or interactions with vibrations. However, these approaches are less suitable to control microwave photon propagation inside integrated superconducting quantum devices. Here, we demonstrate on-demand tunable directional scattering based on two periodically modulated transmon qubits coupled to a transmission line at a fixed distance. By changing the relative phase between the modulation tones, we realize unidirectional forward or backward photon scattering. Such an in-situ switchable mirror represents a versatile tool for intra- and inter-chip microwave photonic processors. In the future, a lattice of qubits can be used to realize topological circuits that exhibit strong nonreciprocity or chirality. acknowledged_ssus: - _id: M-Shop - _id: NanoFab acknowledgement: The authors thank W.D. Oliver for discussions, L. Drmic and P. Zielinski for software development, and the MIBA workshop and the IST nanofabrication facility for technical support. This work was supported by the Austrian Science Fund (FWF) through BeyondC (F7105) and IST Austria. E.R. is the recipient of a DOC fellowship of the Austrian Academy of Sciences at IST Austria. J.M.F. and M.Z. acknowledge support from the European Research Council under grant agreement No 758053 (ERC StG QUNNECT) and a NOMIS foundation research grant. The work of A.N.P. and A.V.P. has been supported by the Russian Science Foundation under the grant No 20-12-00194. article_number: '2998' article_processing_charge: No article_type: original arxiv: 1 author: - first_name: Elena full_name: Redchenko, Elena id: 2C21D6E8-F248-11E8-B48F-1D18A9856A87 last_name: Redchenko - first_name: Alexander V. full_name: Poshakinskiy, Alexander V. last_name: Poshakinskiy - first_name: Riya full_name: Sett, Riya id: 2E6D040E-F248-11E8-B48F-1D18A9856A87 last_name: Sett orcid: 0000-0001-7641-8348 - first_name: Martin full_name: Zemlicka, Martin id: 2DCF8DE6-F248-11E8-B48F-1D18A9856A87 last_name: Zemlicka orcid: 0009-0005-0878-3032 - first_name: Alexander N. full_name: Poddubny, Alexander N. last_name: Poddubny - first_name: Johannes M full_name: Fink, Johannes M id: 4B591CBA-F248-11E8-B48F-1D18A9856A87 last_name: Fink orcid: 0000-0001-8112-028X citation: ama: Redchenko E, Poshakinskiy AV, Sett R, Zemlicka M, Poddubny AN, Fink JM. Tunable directional photon scattering from a pair of superconducting qubits. Nature Communications. 2023;14. doi:10.1038/s41467-023-38761-6 apa: Redchenko, E., Poshakinskiy, A. V., Sett, R., Zemlicka, M., Poddubny, A. N., & Fink, J. M. (2023). Tunable directional photon scattering from a pair of superconducting qubits. Nature Communications. Springer Nature. https://doi.org/10.1038/s41467-023-38761-6 chicago: Redchenko, Elena, Alexander V. Poshakinskiy, Riya Sett, Martin Zemlicka, Alexander N. Poddubny, and Johannes M Fink. “Tunable Directional Photon Scattering from a Pair of Superconducting Qubits.” Nature Communications. Springer Nature, 2023. https://doi.org/10.1038/s41467-023-38761-6. ieee: E. Redchenko, A. V. Poshakinskiy, R. Sett, M. Zemlicka, A. N. Poddubny, and J. M. Fink, “Tunable directional photon scattering from a pair of superconducting qubits,” Nature Communications, vol. 14. Springer Nature, 2023. ista: Redchenko E, Poshakinskiy AV, Sett R, Zemlicka M, Poddubny AN, Fink JM. 2023. Tunable directional photon scattering from a pair of superconducting qubits. Nature Communications. 14, 2998. mla: Redchenko, Elena, et al. “Tunable Directional Photon Scattering from a Pair of Superconducting Qubits.” Nature Communications, vol. 14, 2998, Springer Nature, 2023, doi:10.1038/s41467-023-38761-6. short: E. Redchenko, A.V. Poshakinskiy, R. Sett, M. Zemlicka, A.N. Poddubny, J.M. Fink, Nature Communications 14 (2023). corr_author: '1' date_created: 2023-06-04T22:01:02Z date_published: 2023-05-24T00:00:00Z date_updated: 2026-05-15T22:31:23Z day: '24' ddc: - '530' department: - _id: JoFi doi: 10.1038/s41467-023-38761-6 ec_funded: 1 external_id: arxiv: - '2205.03293' isi: - '001001099700002' pmid: - '37225689' file: - access_level: open_access checksum: a857df40f0882859c48a1ff1e2001ec2 content_type: application/pdf creator: dernst date_created: 2023-06-06T07:31:20Z date_updated: 2023-06-06T07:31:20Z file_id: '13123' file_name: 2023_NaturePhysics_Redchenko.pdf file_size: 1654389 relation: main_file success: 1 file_date_updated: 2023-06-06T07:31:20Z has_accepted_license: '1' intvolume: ' 14' isi: 1 language: - iso: eng month: '05' oa: 1 oa_version: Published Version pmid: 1 project: - _id: 26336814-B435-11E9-9278-68D0E5697425 call_identifier: H2020 grant_number: '758053' name: A Fiber Optic Transceiver for Superconducting Qubits - _id: 26B354CA-B435-11E9-9278-68D0E5697425 name: Controllable Collective States of Superconducting Qubit Ensembles - _id: eb9b30ac-77a9-11ec-83b8-871f581d53d2 name: Protected states of quantum matter - _id: bdb108fd-d553-11ed-ba76-83dc74a9864f grant_number: F07105 name: QUANTUM INFORMATION SYSTEMS BEYOND CLASSICAL CAPABILITIES / P5- Integration of Superconducting Quantum Circuits publication: Nature Communications publication_identifier: eissn: - 2041-1723 publication_status: published publisher: Springer Nature quality_controlled: '1' related_material: record: - id: '13124' relation: research_data status: public - id: '19533' relation: dissertation_contains status: public scopus_import: '1' status: public title: Tunable directional photon scattering from a pair of superconducting qubits tmp: image: /images/cc_by.png legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0) short: CC BY (4.0) type: journal_article user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87 volume: 14 year: '2023' ... --- _id: '10924' abstract: - lang: eng text: Solid-state microwave systems offer strong interactions for fast quantum logic and sensing but photons at telecom wavelength are the ideal choice for high-density low-loss quantum interconnects. A general-purpose interface that can make use of single photon effects requires < 1 input noise quanta, which has remained elusive due to either low efficiency or pump induced heating. Here we demonstrate coherent electro-optic modulation on nanosecond-timescales with only 0.16+0.02−0.01 microwave input noise photons with a total bidirectional transduction efficiency of 8.7% (or up to 15% with 0.41+0.02−0.02), as required for near-term heralded quantum network protocols. The use of short and high-power optical pump pulses also enables near-unity cooperativity of the electro-optic interaction leading to an internal pure conversion efficiency of up to 99.5%. Together with the low mode occupancy this provides evidence for electro-optic laser cooling and vacuum amplification as predicted a decade ago. acknowledged_ssus: - _id: M-Shop acknowledgement: "The authors thank S. Wald and F. Diorico for their help with optical filtering, O. Hosten\r\nand M. Aspelmeyer for equipment, H.G.L. Schwefel for materials and discussions, L.\r\nDrmic and P. Zielinski for software support, and the MIBA workshop at IST Austria for\r\nmachining the microwave cavity. This work was supported by the European Research\r\nCouncil under grant agreement no. 758053 (ERC StG QUNNECT) and the European\r\nUnion’s Horizon 2020 research and innovation program under grant agreement no.\r\n899354 (FETopen SuperQuLAN). W.H. is the recipient of an ISTplus postdoctoral fellowship\r\nwith funding from the European Union’s Horizon 2020 research and innovation\r\nprogram under the Marie Skłodowska-Curie grant agreement no. 754411. G.A. is the\r\nrecipient of a DOC fellowship of the Austrian Academy of Sciences at IST Austria. J.M.F.\r\nacknowledges support from the Austrian Science Fund (FWF) through BeyondC (F7105)\r\nand the European Union’s Horizon 2020 research and innovation programs under grant\r\nagreement no. 862644 (FETopen QUARTET)." article_number: '1276' article_processing_charge: No article_type: original arxiv: 1 author: - first_name: Rishabh full_name: Sahu, Rishabh id: 47D26E34-F248-11E8-B48F-1D18A9856A87 last_name: Sahu orcid: 0000-0001-6264-2162 - first_name: William J full_name: Hease, William J id: 29705398-F248-11E8-B48F-1D18A9856A87 last_name: Hease orcid: 0000-0001-9868-2166 - first_name: Alfredo R full_name: Rueda Sanchez, Alfredo R id: 3B82B0F8-F248-11E8-B48F-1D18A9856A87 last_name: Rueda Sanchez orcid: 0000-0001-6249-5860 - first_name: Georg M full_name: Arnold, Georg M id: 3770C838-F248-11E8-B48F-1D18A9856A87 last_name: Arnold orcid: 0000-0003-1397-7876 - first_name: Liu full_name: Qiu, Liu id: 45e99c0d-1eb1-11eb-9b96-ed8ab2983cac last_name: Qiu orcid: 0000-0003-4345-4267 - first_name: Johannes M full_name: Fink, Johannes M id: 4B591CBA-F248-11E8-B48F-1D18A9856A87 last_name: Fink orcid: 0000-0001-8112-028X citation: ama: Sahu R, Hease WJ, Rueda Sanchez AR, Arnold GM, Qiu L, Fink JM. Quantum-enabled operation of a microwave-optical interface. Nature Communications. 2022;13. doi:10.1038/s41467-022-28924-2 apa: Sahu, R., Hease, W. J., Rueda Sanchez, A. R., Arnold, G. M., Qiu, L., & Fink, J. M. (2022). Quantum-enabled operation of a microwave-optical interface. Nature Communications. Springer Nature. https://doi.org/10.1038/s41467-022-28924-2 chicago: Sahu, Rishabh, William J Hease, Alfredo R Rueda Sanchez, Georg M Arnold, Liu Qiu, and Johannes M Fink. “Quantum-Enabled Operation of a Microwave-Optical Interface.” Nature Communications. Springer Nature, 2022. https://doi.org/10.1038/s41467-022-28924-2. ieee: R. Sahu, W. J. Hease, A. R. Rueda Sanchez, G. M. Arnold, L. Qiu, and J. M. Fink, “Quantum-enabled operation of a microwave-optical interface,” Nature Communications, vol. 13. Springer Nature, 2022. ista: Sahu R, Hease WJ, Rueda Sanchez AR, Arnold GM, Qiu L, Fink JM. 2022. Quantum-enabled operation of a microwave-optical interface. Nature Communications. 13, 1276. mla: Sahu, Rishabh, et al. “Quantum-Enabled Operation of a Microwave-Optical Interface.” Nature Communications, vol. 13, 1276, Springer Nature, 2022, doi:10.1038/s41467-022-28924-2. short: R. Sahu, W.J. Hease, A.R. Rueda Sanchez, G.M. Arnold, L. Qiu, J.M. Fink, Nature Communications 13 (2022). corr_author: '1' date_created: 2022-03-27T22:01:45Z date_published: 2022-03-11T00:00:00Z date_updated: 2026-05-15T22:31:21Z day: '11' ddc: - '530' department: - _id: JoFi doi: 10.1038/s41467-022-28924-2 ec_funded: 1 external_id: arxiv: - '2107.08303' isi: - '000767892300013' pmid: - '35277488' file: - access_level: open_access checksum: 7c5176db7b8e2ed18a4e0c5aca70a72c content_type: application/pdf creator: dernst date_created: 2022-03-28T08:02:12Z date_updated: 2022-03-28T08:02:12Z file_id: '10929' file_name: 2022_NatureCommunications_Sahu.pdf file_size: 1167492 relation: main_file success: 1 file_date_updated: 2022-03-28T08:02:12Z has_accepted_license: '1' intvolume: ' 13' isi: 1 language: - iso: eng month: '03' oa: 1 oa_version: Published Version pmid: 1 project: - _id: 26336814-B435-11E9-9278-68D0E5697425 call_identifier: H2020 grant_number: '758053' name: A Fiber Optic Transceiver for Superconducting Qubits - _id: 9B868D20-BA93-11EA-9121-9846C619BF3A call_identifier: H2020 grant_number: '899354' name: Quantum Local Area Networks with Superconducting Qubits - _id: 260C2330-B435-11E9-9278-68D0E5697425 call_identifier: H2020 grant_number: '754411' name: ISTplus - Postdoctoral Fellowships - _id: 237CBA6C-32DE-11EA-91FC-C7463DDC885E call_identifier: H2020 grant_number: '862644' name: Quantum readout techniques and technologies - _id: bdb108fd-d553-11ed-ba76-83dc74a9864f grant_number: F07105 name: QUANTUM INFORMATION SYSTEMS BEYOND CLASSICAL CAPABILITIES / P5- Integration of Superconducting Quantum Circuits publication: Nature Communications publication_identifier: eissn: - 2041-1723 publication_status: published publisher: Springer Nature quality_controlled: '1' related_material: record: - id: '13175' relation: dissertation_contains status: public - id: '12900' relation: dissertation_contains status: public - id: '18871' relation: dissertation_contains status: public scopus_import: '1' status: public title: Quantum-enabled operation of a microwave-optical interface tmp: image: /images/cc_by.png legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0) short: CC BY (4.0) type: journal_article user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87 volume: 13 year: '2022' ... --- _id: '9928' abstract: - lang: eng text: There are two elementary superconducting qubit types that derive directly from the quantum harmonic oscillator. In one, the inductor is replaced by a nonlinear Josephson junction to realize the widely used charge qubits with a compact phase variable and a discrete charge wave function. In the other, the junction is added in parallel, which gives rise to an extended phase variable, continuous wave functions, and a rich energy-level structure due to the loop topology. While the corresponding rf superconducting quantum interference device Hamiltonian was introduced as a quadratic quasi-one-dimensional potential approximation to describe the fluxonium qubit implemented with long Josephson-junction arrays, in this work we implement it directly using a linear superinductor formed by a single uninterrupted aluminum wire. We present a large variety of qubits, all stemming from the same circuit but with drastically different characteristic energy scales. This includes flux and fluxonium qubits but also the recently introduced quasicharge qubit with strongly enhanced zero-point phase fluctuations and a heavily suppressed flux dispersion. The use of a geometric inductor results in high reproducibility of the inductive energy as guaranteed by top-down lithography—a key ingredient for intrinsically protected superconducting qubits. acknowledged_ssus: - _id: NanoFab - _id: M-Shop acknowledgement: We thank W. Hughes for analytic and numerical modeling during the early stages of this work, J. Koch for discussions and support with the scqubits package, R. Sett, P. Zielinski, and L. Drmic for software development, and G. Katsaros for equipment support, as well as the MIBA workshop and the Institute of Science and Technology Austria nanofabrication facility. We thank I. Pop, S. Deleglise, and E. Flurin for discussions. This work was supported by a NOMIS Foundation research grant, the Austrian Science Fund (FWF) through BeyondC (F7105), and IST Austria. M.P. is the recipient of a Pöttinger scholarship at IST Austria. E.R. is the recipient of a DOC fellowship of the Austrian Academy of Sciences at IST Austria. article_processing_charge: No article_type: original arxiv: 1 author: - first_name: Matilda full_name: Peruzzo, Matilda id: 3F920B30-F248-11E8-B48F-1D18A9856A87 last_name: Peruzzo orcid: 0000-0002-3415-4628 - first_name: Farid full_name: Hassani, Farid id: 2AED110C-F248-11E8-B48F-1D18A9856A87 last_name: Hassani orcid: 0000-0001-6937-5773 - first_name: Gregory full_name: Szep, Gregory last_name: Szep - first_name: Andrea full_name: Trioni, Andrea id: 42F71B44-F248-11E8-B48F-1D18A9856A87 last_name: Trioni - first_name: Elena full_name: Redchenko, Elena id: 2C21D6E8-F248-11E8-B48F-1D18A9856A87 last_name: Redchenko - first_name: Martin full_name: Zemlicka, Martin id: 2DCF8DE6-F248-11E8-B48F-1D18A9856A87 last_name: Zemlicka orcid: 0009-0005-0878-3032 - first_name: Johannes M full_name: Fink, Johannes M id: 4B591CBA-F248-11E8-B48F-1D18A9856A87 last_name: Fink orcid: 0000-0001-8112-028X citation: ama: 'Peruzzo M, Hassani F, Szep G, et al. Geometric superinductance qubits: Controlling phase delocalization across a single Josephson junction. PRX Quantum. 2021;2(4):040341. doi:10.1103/PRXQuantum.2.040341' apa: 'Peruzzo, M., Hassani, F., Szep, G., Trioni, A., Redchenko, E., Zemlicka, M., & Fink, J. M. (2021). Geometric superinductance qubits: Controlling phase delocalization across a single Josephson junction. PRX Quantum. American Physical Society. https://doi.org/10.1103/PRXQuantum.2.040341' chicago: 'Peruzzo, Matilda, Farid Hassani, Gregory Szep, Andrea Trioni, Elena Redchenko, Martin Zemlicka, and Johannes M Fink. “Geometric Superinductance Qubits: Controlling Phase Delocalization across a Single Josephson Junction.” PRX Quantum. American Physical Society, 2021. https://doi.org/10.1103/PRXQuantum.2.040341.' ieee: 'M. Peruzzo et al., “Geometric superinductance qubits: Controlling phase delocalization across a single Josephson junction,” PRX Quantum, vol. 2, no. 4. American Physical Society, p. 040341, 2021.' ista: 'Peruzzo M, Hassani F, Szep G, Trioni A, Redchenko E, Zemlicka M, Fink JM. 2021. Geometric superinductance qubits: Controlling phase delocalization across a single Josephson junction. PRX Quantum. 2(4), 040341.' mla: 'Peruzzo, Matilda, et al. “Geometric Superinductance Qubits: Controlling Phase Delocalization across a Single Josephson Junction.” PRX Quantum, vol. 2, no. 4, American Physical Society, 2021, p. 040341, doi:10.1103/PRXQuantum.2.040341.' short: M. Peruzzo, F. Hassani, G. Szep, A. Trioni, E. Redchenko, M. Zemlicka, J.M. Fink, PRX Quantum 2 (2021) 040341. corr_author: '1' date_created: 2021-08-17T08:14:18Z date_published: 2021-11-24T00:00:00Z date_updated: 2026-04-15T06:41:46Z day: '24' ddc: - '530' department: - _id: JoFi - _id: NanoFab - _id: M-Shop doi: 10.1103/PRXQuantum.2.040341 ec_funded: 1 external_id: arxiv: - '2106.05882' isi: - '000723015100001' file: - access_level: open_access checksum: 36eb41ea43d8ca22b0efab12419e4eb2 content_type: application/pdf creator: cchlebak date_created: 2022-01-18T11:29:33Z date_updated: 2022-01-18T11:29:33Z file_id: '10641' file_name: 2021_PRXQuantum_Peruzzo.pdf file_size: 4247422 relation: main_file success: 1 file_date_updated: 2022-01-18T11:29:33Z has_accepted_license: '1' intvolume: ' 2' isi: 1 issue: '4' keyword: - quantum physics - mesoscale and nanoscale physics language: - iso: eng month: '11' oa: 1 oa_version: Published Version page: '040341' project: - _id: 2564DBCA-B435-11E9-9278-68D0E5697425 call_identifier: H2020 grant_number: '665385' name: International IST Doctoral Program - _id: 2622978C-B435-11E9-9278-68D0E5697425 name: Hybrid Semiconductor - Superconductor Quantum Devices - _id: bdb108fd-d553-11ed-ba76-83dc74a9864f grant_number: F07105 name: QUANTUM INFORMATION SYSTEMS BEYOND CLASSICAL CAPABILITIES / P5- Integration of Superconducting Quantum Circuits publication: PRX Quantum publication_identifier: eissn: - 2691-3399 publication_status: published publisher: American Physical Society quality_controlled: '1' related_material: record: - id: '13057' relation: research_data status: public - id: '9920' relation: dissertation_contains status: public - id: '17133' relation: dissertation_contains status: public scopus_import: '1' status: public title: 'Geometric superinductance qubits: Controlling phase delocalization across a single Josephson junction' tmp: image: /images/cc_by.png legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0) short: CC BY (4.0) type: journal_article user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87 volume: 2 year: '2021' ... --- _id: '8038' abstract: - lang: eng text: Microelectromechanical systems and integrated photonics provide the basis for many reliable and compact circuit elements in modern communication systems. Electro-opto-mechanical devices are currently one of the leading approaches to realize ultra-sensitive, low-loss transducers for an emerging quantum information technology. Here we present an on-chip microwave frequency converter based on a planar aluminum on silicon nitride platform that is compatible with slot-mode coupled photonic crystal cavities. We show efficient frequency conversion between two propagating microwave modes mediated by the radiation pressure interaction with a metalized dielectric nanobeam oscillator. We achieve bidirectional coherent conversion with a total device efficiency of up to ~60%, a dynamic range of 2 × 10^9 photons/s and an instantaneous bandwidth of up to 1.7 kHz. A high fidelity quantum state transfer would be possible if the drive dependent output noise of currently ~14 photons s^−1 Hz^−1 is further reduced. Such a silicon nitride based transducer is in situ reconfigurable and could be used for on-chip classical and quantum signal routing and filtering, both for microwave and hybrid microwave-optical applications. article_number: '034011' article_processing_charge: Yes (via OA deal) article_type: original author: - first_name: Johannes M full_name: Fink, Johannes M id: 4B591CBA-F248-11E8-B48F-1D18A9856A87 last_name: Fink orcid: 0000-0001-8112-028X - first_name: M. full_name: Kalaee, M. last_name: Kalaee - first_name: R. full_name: Norte, R. last_name: Norte - first_name: A. full_name: Pitanti, A. last_name: Pitanti - first_name: O. full_name: Painter, O. last_name: Painter citation: ama: Fink JM, Kalaee M, Norte R, Pitanti A, Painter O. Efficient microwave frequency conversion mediated by a photonics compatible silicon nitride nanobeam oscillator. Quantum Science and Technology. 2020;5(3). doi:10.1088/2058-9565/ab8dce apa: Fink, J. M., Kalaee, M., Norte, R., Pitanti, A., & Painter, O. (2020). Efficient microwave frequency conversion mediated by a photonics compatible silicon nitride nanobeam oscillator. Quantum Science and Technology. IOP Publishing. https://doi.org/10.1088/2058-9565/ab8dce chicago: Fink, Johannes M, M. Kalaee, R. Norte, A. Pitanti, and O. Painter. “Efficient Microwave Frequency Conversion Mediated by a Photonics Compatible Silicon Nitride Nanobeam Oscillator.” Quantum Science and Technology. IOP Publishing, 2020. https://doi.org/10.1088/2058-9565/ab8dce. ieee: J. M. Fink, M. Kalaee, R. Norte, A. Pitanti, and O. Painter, “Efficient microwave frequency conversion mediated by a photonics compatible silicon nitride nanobeam oscillator,” Quantum Science and Technology, vol. 5, no. 3. IOP Publishing, 2020. ista: Fink JM, Kalaee M, Norte R, Pitanti A, Painter O. 2020. Efficient microwave frequency conversion mediated by a photonics compatible silicon nitride nanobeam oscillator. Quantum Science and Technology. 5(3), 034011. mla: Fink, Johannes M., et al. “Efficient Microwave Frequency Conversion Mediated by a Photonics Compatible Silicon Nitride Nanobeam Oscillator.” Quantum Science and Technology, vol. 5, no. 3, 034011, IOP Publishing, 2020, doi:10.1088/2058-9565/ab8dce. short: J.M. Fink, M. Kalaee, R. Norte, A. Pitanti, O. Painter, Quantum Science and Technology 5 (2020). corr_author: '1' date_created: 2020-06-29T07:59:35Z date_published: 2020-05-25T00:00:00Z date_updated: 2026-04-15T06:42:07Z day: '25' ddc: - '530' department: - _id: JoFi doi: 10.1088/2058-9565/ab8dce ec_funded: 1 external_id: isi: - '000539300800001' file: - access_level: open_access checksum: 8f25f05053f511f892ae8fa93f341e61 content_type: application/pdf creator: cziletti date_created: 2020-06-30T10:29:10Z date_updated: 2020-07-14T12:48:08Z file_id: '8072' file_name: 2020_QuantumSciTechnol_Fink.pdf file_size: 2600967 relation: main_file file_date_updated: 2020-07-14T12:48:08Z has_accepted_license: '1' intvolume: ' 5' isi: 1 issue: '3' language: - iso: eng month: '05' oa: 1 oa_version: Published Version project: - _id: 26336814-B435-11E9-9278-68D0E5697425 call_identifier: H2020 grant_number: '758053' name: A Fiber Optic Transceiver for Superconducting Qubits - _id: 257EB838-B435-11E9-9278-68D0E5697425 call_identifier: H2020 grant_number: '732894' name: Hybrid Optomechanical Technologies - _id: 2622978C-B435-11E9-9278-68D0E5697425 name: Hybrid Semiconductor - Superconductor Quantum Devices - _id: bdb108fd-d553-11ed-ba76-83dc74a9864f grant_number: F07105 name: QUANTUM INFORMATION SYSTEMS BEYOND CLASSICAL CAPABILITIES / P5- Integration of Superconducting Quantum Circuits publication: Quantum Science and Technology publication_identifier: eissn: - 2058-9565 publication_status: published publisher: IOP Publishing quality_controlled: '1' scopus_import: '1' status: public title: Efficient microwave frequency conversion mediated by a photonics compatible silicon nitride nanobeam oscillator tmp: image: /images/cc_by.png legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0) short: CC BY (4.0) type: journal_article user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87 volume: 5 year: '2020' ...