[{"_id":"21863","oa_version":"Published Version","department":[{"_id":"GradSch"},{"_id":"JoFi"}],"project":[{"_id":"bdadfa0d-d553-11ed-ba76-fb85edbd456a","grant_number":"101089099","name":"Cavity Quantum Electro Optics: Microwave photonics with nonclassical states"},{"call_identifier":"H2020","_id":"9B868D20-BA93-11EA-9121-9846C619BF3A","name":"Quantum Local Area Networks with Superconducting Qubits","grant_number":"899354"},{"name":"A Fiber Optic Transceiver for Superconducting Qubits","grant_number":"758053","call_identifier":"H2020","_id":"26336814-B435-11E9-9278-68D0E5697425"},{"_id":"5b807754-ab3d-11f0-914f-ff8c34502cc9","name":"Integrated optical coupling for low loss electro-optic interconnects","grant_number":"101248662"},{"_id":"91aaf765-16d5-11f0-9cad-a8e7e44cccb7","name":"Cavity-Integrated Electro-Optics: Measuring, Converting and Manipulating Microwaves with Light","grant_number":"101187231"},{"_id":"bdb108fd-d553-11ed-ba76-83dc74a9864f","name":"QUANTUM INFORMATION SYSTEMS BEYOND CLASSICAL CAPABILITIES / P5- Integration of Superconducting Quantum Circuits","grant_number":"F07105"},{"_id":"bdb7cfc1-d553-11ed-ba76-d2eaab167738","grant_number":"101080139","name":"Open Superconducting Quantum Computers (OpenSuperQPlus)"},{"name":"NOMIS Fellowship Program","_id":"9B861AAC-BA93-11EA-9121-9846C619BF3A"}],"tmp":{"image":"/images/cc_by.png","short":"CC BY (4.0)","name":"Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)","legal_code_url":"https://creativecommons.org/licenses/by/4.0/legalcode"},"citation":{"short":"T. Werner, Interfacing Superconducting Qubits with Optical Photons, Institute of Science and Technology Austria, 2026.","chicago":"Werner, Thomas. “Interfacing Superconducting Qubits with Optical Photons.” Institute of Science and Technology Austria, 2026. <a href=\"https://doi.org/10.15479/AT-ISTA-21863\">https://doi.org/10.15479/AT-ISTA-21863</a>.","apa":"Werner, T. (2026). <i>Interfacing superconducting qubits with optical photons</i>. Institute of Science and Technology Austria. <a href=\"https://doi.org/10.15479/AT-ISTA-21863\">https://doi.org/10.15479/AT-ISTA-21863</a>","ama":"Werner T. Interfacing superconducting qubits with optical photons. 2026. doi:<a href=\"https://doi.org/10.15479/AT-ISTA-21863\">10.15479/AT-ISTA-21863</a>","ista":"Werner T. 2026. Interfacing superconducting qubits with optical photons. Institute of Science and Technology Austria.","ieee":"T. Werner, “Interfacing superconducting qubits with optical photons,” Institute of Science and Technology Austria, 2026.","mla":"Werner, Thomas. <i>Interfacing Superconducting Qubits with Optical Photons</i>. Institute of Science and Technology Austria, 2026, doi:<a href=\"https://doi.org/10.15479/AT-ISTA-21863\">10.15479/AT-ISTA-21863</a>."},"doi":"10.15479/AT-ISTA-21863","author":[{"orcid":"0009-0001-2346-5236","last_name":"Werner","first_name":"Thomas","id":"1fcd8497-dba3-11ea-a45e-c6fbd715f7c7","full_name":"Werner, Thomas"}],"date_updated":"2026-05-20T13:35:43Z","title":"Interfacing superconducting qubits with optical photons","related_material":{"record":[{"relation":"part_of_dissertation","id":"19073","status":"public"},{"id":"21870","relation":"part_of_dissertation","status":"public"}]},"file_date_updated":"2026-05-15T15:54:06Z","publication_identifier":{"issn":["2663-337X"]},"acknowledgement":"The author of this work was supported by the European Research Council under grant no.\r\n101089099 (ERC CoG cQEO) and the European Union’s Horizon 2020 research and innovation\r\nprogram under grant no. 899354 (FETopen SuperQuLAN).\r\nThis work was also supported by the European Research Council under grant nos. 758053\r\n(ERC StG QUNNECT), 101248662 (ERC POC CoupledEOT), and the European Innovation\r\nCouncil no. 101187231 (PathfinderOpen CIELO). This research was funded in whole or in part\r\nby the Austrian Science Fund (FWF) [10.55776/F71]. For open access purposes, the author\r\nhas applied a CC BY public copyright license to any author accepted manuscript version arising\r\nfrom this submission.\r\niii\r\nMy co-authors in the works mentioned later acknowledge generous support from the ISTFELLOW program, the NOMIS-ISTA fellowship, the Horizon Europe Program HORIZONCL4-2022-QUANTUM-01-SGA via Project No. 101113946 OpenSuperQPlus100 and a DOC fellowship of the Austrian Academy of Sciences at IST Austria.\r\n","day":"12","OA_place":"publisher","degree_awarded":"PhD","acknowledged_ssus":[{"_id":"M-Shop"},{"_id":"NanoFab"},{"_id":"LifeSc"},{"_id":"SSU"}],"status":"public","month":"05","corr_author":"1","ddc":["530","537","539"],"alternative_title":["ISTA Thesis"],"abstract":[{"text":"Atoms and photons, two things so different but yet so alike. The former, the building block of matter, something we learn about in school and imagine it as some tiny marbles encircled by other tinier marbles. The latter, an electromagnetic wave, a light particle or an excitation of the electromagnetic field. Quantum mechanics tells us about the properties of these two entities. And even if it sounds, looks and writes counter-intuitive, it has proven right for over a century now.\r\n\r\nIn this work, I elaborate on how we tested the laws of quantum mechanics and how we used them learn more about the tiny building blocks of nature and the fields they use to talk to each other. The atoms we use, are artificial. Superconducting qubits, small electrical circuits with quantized energy levels behave like electrons that transition between different orbitals in an atom. One of the qubits' advantages, is also a big disadvantage. We design the circuits' energy levels and fabricate them in a cleanroom. This allows for arbitrary spaced energy levels but in contrast to real atoms, prevents two superconducting qubits from being alike. Still, this qubit platform is one of the frontrunners for future quantum computing technology and testing fundamental physics due to their scalability.\r\n\r\nWe interface superconducting qubits, which operate in the GHz regime, with microwave photons. We use 3D aluminum cavities as mediators between qubits and photons. The cavities allow for non-destructive readout of the qubit state, they shield the qubits from noise at the qubit frequency and they give us an easy way to frequency-tune these joint systems.\r\n\r\nWe need to operate superconducting qubits and their cavities at millikelvin temperatures in dilution refrigerators. At higher temperatures, superconductivity suffers and even worse, the environment is filled with thermal noise photons. This poses a fundamental limitation on the scalability of superconducting qubit devices. Also connecting multiple devices in different fridges does not work over room temperature links because the microwave photons used for this purpose will be covered in noise and the quantum information they carry, will be unusable.\r\n\r\nInfrared photons do not suffer from this noise problem since there are close to zero thermal noise photons at their frequencies at room temperature. We cannot simply interface superconducting devices with optical photons due their frequency mismatch and the destructive effect of optical photons on superconductors. Therefore, we use microwave-to-optics transducers that allow to convert microwave photons into optical ones and vice-versa. The transducers that we use are macroscopic electro-optic transducers using the Pockels effect in a disk-shaped Lithium Niobate whispering gallery mode resonator. By using a strong optical pump, photons from the two frequency domains experience a beam-splitter interaction and get converted from one to the other.\r\n\r\nWe measure the generated optical photons using elaborate optical setups, optical heterodyning and single photon detectors to gain knowledge about the qubit state or the converted microwave photons. Bridging the microwave and the optical world allows us to take advantage of both of their strengths but it also requires deep knowledge about both of their working principles.\r\n\r\nIn this work, we describe two experiments that our group conducted to showcase the opportunities that arise from interfacing superconducting qubits with optical photons but also the pitfalls, one may encounter on the way.\r\n\r\nIn the first experiment, we managed to all-optically read out a superconducting qubit. We show that the assignment fidelity, the probability that a measurement of the qubit state matches the prepared state, is close to equal for all-optical, microwave-to-optics and conventional microwave readout. We show T1 and T2 measurements for all three readout types and give an analysis of the noise caused by the optics. Finally, we show that the infrared light does not affect the qubit performance in a negative way but that the heating it causes does. This is an important insight that we used in the next experiment.\r\n\r\nThe second experiment is the upconversion of itinerant single microwave photons to the optical domain. We show that we can generate single microwave photons from a qubit-cavity system. We upconvert these single photons, measure them with a single photon detector and reconstruct their shape. By conducting a single photon Rabi measurement, we show correlations between the microwave and the optical domain. And by thorough signal-to-noise measurements and noise analysis, we find that we can generate single infrared photons with high signal-to-noise ratio 5.1 and low transducer added noise (<0.012 quanta). We show that this measurement creates a path towards entanglement of a superconducting qubit and an optical photon and what parameters need to be improved to achieve it. Additionally, this experiment is a proof of principle for an on-demand infrared single photon source. More generally, it allows to link microwave quantum technology in general to the optical domain.","lang":"eng"}],"has_accepted_license":"1","date_created":"2026-05-12T09:04:02Z","publisher":"Institute of Science and Technology Austria","supervisor":[{"orcid":"0000-0001-8112-028X","last_name":"Fink","first_name":"Johannes M","id":"4B591CBA-F248-11E8-B48F-1D18A9856A87","full_name":"Fink, Johannes M"}],"language":[{"iso":"eng"}],"year":"2026","keyword":["Superconducting qubits","Quantum optics","Single photons and quantum effects","Nonlinear optics"],"article_processing_charge":"No","publication_status":"published","file":[{"date_updated":"2026-05-15T15:53:57Z","file_id":"21879","access_level":"open_access","content_type":"application/pdf","file_size":9330516,"file_name":"2026_Werner_Thomas_Thesis.pdf","checksum":"a5b4d8dba83f96e955a3625c0eebee98","creator":"twerner","date_created":"2026-05-15T15:53:57Z","relation":"main_file"},{"file_id":"21880","date_updated":"2026-05-15T15:54:06Z","creator":"twerner","file_name":"2026_Werner_Thomas_Thesis.zip","checksum":"b41282beaacfb32472769b9e3b1758d8","relation":"source_file","date_created":"2026-05-15T15:54:06Z","content_type":"application/x-zip-compressed","access_level":"closed","file_size":9370704}],"user_id":"8b945eb4-e2f2-11eb-945a-df72226e66a9","date_published":"2026-05-12T00:00:00Z","page":"97","type":"dissertation","ec_funded":1,"oa":1},{"OA_place":"publisher","file_date_updated":"2026-06-15T22:30:03Z","related_material":{"record":[{"relation":"part_of_dissertation","id":"14759","status":"public"}]},"publication_identifier":{"issn":["2663-337X"],"isbn":["978-3-99078-075-6"]},"day":"11","date_updated":"2026-07-24T08:07:28Z","title":"Atoms in a propagating-wave cavity for squeezed Mach-Zehnder atom interferometry","author":[{"first_name":"Sebastian","last_name":"Wald","orcid":"0000-0002-5869-1604","full_name":"Wald, Sebastian","id":"133F200A-B015-11E9-AD41-0EDAE5697425"}],"tmp":{"image":"/images/cc_by_nc.png","legal_code_url":"https://creativecommons.org/licenses/by-nc/4.0/legalcode","name":"Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)","short":"CC BY-NC (4.0)"},"doi":"10.15479/AT-ISTA-20798","citation":{"apa":"Wald, S. (2025). <i>Atoms in a propagating-wave cavity for squeezed Mach-Zehnder atom interferometry</i>. Institute of Science and Technology Austria. <a href=\"https://doi.org/10.15479/AT-ISTA-20798\">https://doi.org/10.15479/AT-ISTA-20798</a>","ista":"Wald S. 2025. Atoms in a propagating-wave cavity for squeezed Mach-Zehnder atom interferometry. Institute of Science and Technology Austria.","ama":"Wald S. Atoms in a propagating-wave cavity for squeezed Mach-Zehnder atom interferometry. 2025. doi:<a href=\"https://doi.org/10.15479/AT-ISTA-20798\">10.15479/AT-ISTA-20798</a>","ieee":"S. Wald, “Atoms in a propagating-wave cavity for squeezed Mach-Zehnder atom interferometry,” Institute of Science and Technology Austria, 2025.","mla":"Wald, Sebastian. <i>Atoms in a Propagating-Wave Cavity for Squeezed Mach-Zehnder Atom Interferometry</i>. Institute of Science and Technology Austria, 2025, doi:<a href=\"https://doi.org/10.15479/AT-ISTA-20798\">10.15479/AT-ISTA-20798</a>.","short":"S. Wald, Atoms in a Propagating-Wave Cavity for Squeezed Mach-Zehnder Atom Interferometry, Institute of Science and Technology Austria, 2025.","chicago":"Wald, Sebastian. “Atoms in a Propagating-Wave Cavity for Squeezed Mach-Zehnder Atom Interferometry.” Institute of Science and Technology Austria, 2025. <a href=\"https://doi.org/10.15479/AT-ISTA-20798\">https://doi.org/10.15479/AT-ISTA-20798</a>."},"OA_embargo":"6","department":[{"_id":"GradSch"},{"_id":"OnHo"}],"doi_confirm":"1","oa_version":"Published Version","_id":"20798","oa":1,"type":"dissertation","page":"152","date_published":"2025-12-11T00:00:00Z","user_id":"8b945eb4-e2f2-11eb-945a-df72226e66a9","file":[{"date_created":"2025-12-12T11:53:42Z","relation":"main_file","checksum":"1be72faf529a5e8a2d03cb3d5f808b77","creator":"swald","file_name":"2025_Wald_Sebastian_Thesis.pdf","file_size":47536855,"access_level":"open_access","content_type":"application/pdf","embargo":"2026-06-15","file_id":"20809","date_updated":"2026-06-15T22:30:03Z"},{"date_updated":"2026-06-15T22:30:03Z","embargo_to":"open_access","file_id":"20810","access_level":"closed","content_type":"application/x-zip-compressed","file_size":40127601,"creator":"swald","file_name":"2025_Wald_Sebastian_Thesis.zip","checksum":"8c3a1904dceb4bcd04bc9f14b2594bab","date_created":"2025-12-12T11:54:55Z","relation":"source_file"}],"article_processing_charge":"No","year":"2025","keyword":["entanglement-enhanced atom interferometry","cavity QED","spin-squeezing","dipole trap","quantum optics"],"publication_status":"published","language":[{"iso":"eng"}],"supervisor":[{"id":"4C02D85E-F248-11E8-B48F-1D18A9856A87","full_name":"Hosten, Onur","first_name":"Onur","orcid":"0000-0002-2031-204X","last_name":"Hosten"}],"publisher":"Institute of Science and Technology Austria","alternative_title":["ISTA Thesis"],"abstract":[{"text":"Atom interferometers measure the relative phase shifts between coherent matter-wave paths\r\nthat arise from interactions with external fields or inertial forces. Due to their exceptional\r\nphase sensitivity, atom interferometers became an essential tool for precision measurements\r\nand fundamental physics experiments, finding applications in geodesy, gravimetry, and inertial\r\nnavigation. However, their measurement precision is limited by quantum projection noise,\r\nwhich arises from the Heisenberg uncertainty principle, preventing the measurement of atomic\r\nstates with absolute precision. The generation of entanglement between the atoms offers a\r\npath to surpass this so-called standard quantum limit, thereby enhancing the interferometer’s\r\nphase sensitivity beyond classical measurement bounds.\r\nThis thesis reports on the development of an atom interferometer experiment designed to\r\nrealize cavity-mediated, squeezed Mach-Zehnder-type interferometry with ultra-cold 87Rb atoms.\r\nThe experiment combines cavity-aided spin-squeezing with cavity-mediated Mach-Zehnder\r\ninterferometry to demonstrate entanglement-enhanced phase sensitivity. The experiment is\r\ncentered on a triangular optical cavity that mediates all relevant atom-light interactions. The\r\ncavity provides optical trapping, spin-squeezing, and Raman beam-splitter operations, enabling\r\nto perform interferometry on a continuously trapped atomic ensemble.\r\nThe thesis elaborates on the fundamental theoretical framework, the cavity design, and the full\r\noptical setup, including the detailed configuration of the developed laser stabilization methods.\r\nExperimentally, continuous loading methods were explored, resulting in an accumulation of\r\nup to 4 × 106\r\natoms in the dipole trap within a cycle time of 500 ms. The AC Stark shift\r\ncompensation method developed for continuous loading was further applied for in-trap cooling\r\nto 10 µK, and optical pumping for efficient atomic state preparation. Coherent state control\r\nwas verified via observation of microwave-driven Rabi oscillations, and used to characterize\r\natom-cavity coupling.\r\nThese presented results establish the experimental groundwork for the future development of\r\ncavity-mediated, entanglement-enhanced Mach-Zehnder-type atom interferometry.","lang":"eng"}],"date_created":"2025-12-11T11:48:11Z","has_accepted_license":"1","month":"12","corr_author":"1","ddc":["530"],"status":"public","das_tickbox":"1","degree_awarded":"PhD"},{"degree_awarded":"PhD","corr_author":"1","ddc":["530"],"month":"04","status":"public","acknowledged_ssus":[{"_id":"ScienComp"},{"_id":"M-Shop"},{"_id":"NanoFab"},{"_id":"LifeSc"},{"_id":"SSU"}],"has_accepted_license":"1","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"}],"date_created":"2025-04-09T16:44:26Z","alternative_title":["ISTA Thesis"],"publisher":"Institute of Science and Technology Austria","supervisor":[{"orcid":"0000-0001-8112-028X","last_name":"Fink","first_name":"Johannes M","id":"4B591CBA-F248-11E8-B48F-1D18A9856A87","full_name":"Fink, Johannes M"}],"language":[{"iso":"eng"}],"publication_status":"published","year":"2025","article_processing_charge":"No","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"],"file":[{"file_name":"PhD_Thesis_Riya_Sett_pdfa.pdf","creator":"rsett","checksum":"ba6cd2289d0141a160a14fc97df1632f","date_created":"2025-04-10T11:33:22Z","relation":"main_file","access_level":"open_access","content_type":"application/pdf","file_size":4129208,"file_id":"19538","embargo":"2025-10-11","date_updated":"2025-10-11T22:30:02Z"},{"file_name":"PhD Thesis Riya Sett.zip","creator":"rsett","checksum":"ee63a94cb8f7adf5e766903028b81ed6","relation":"source_file","date_created":"2025-04-10T11:34:08Z","content_type":"application/x-zip-compressed","access_level":"closed","file_size":6646110,"file_id":"19539","date_updated":"2025-10-11T22:30:02Z","embargo_to":"open_access"}],"user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","date_published":"2025-04-01T00:00:00Z","page":"109","ec_funded":1,"type":"dissertation","oa":1,"_id":"19533","oa_version":"Published Version","doi_confirm":"1","department":[{"_id":"GradSch"},{"_id":"JoFi"}],"project":[{"call_identifier":"H2020","_id":"237CBA6C-32DE-11EA-91FC-C7463DDC885E","name":"Quantum readout techniques and technologies","grant_number":"862644"},{"name":"QUANTUM INFORMATION SYSTEMS BEYOND CLASSICAL CAPABILITIES / P5- Integration of Superconducting Quantum Circuits","grant_number":"F07105","_id":"bdb108fd-d553-11ed-ba76-83dc74a9864f"}],"citation":{"apa":"Sett, R. (2025). <i>Quantum remote sensing and non-equilibrium phase transitions in the microwave regime</i>. Institute of Science and Technology Austria. <a href=\"https://doi.org/10.15479/AT-ISTA-19533\">https://doi.org/10.15479/AT-ISTA-19533</a>","ama":"Sett R. Quantum remote sensing and non-equilibrium phase transitions in the microwave regime. 2025. doi:<a href=\"https://doi.org/10.15479/AT-ISTA-19533\">10.15479/AT-ISTA-19533</a>","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. <i>Quantum Remote Sensing and Non-Equilibrium Phase Transitions in the Microwave Regime</i>. Institute of Science and Technology Austria, 2025, doi:<a href=\"https://doi.org/10.15479/AT-ISTA-19533\">10.15479/AT-ISTA-19533</a>.","ieee":"R. Sett, “Quantum remote sensing and non-equilibrium phase transitions in the microwave regime,” Institute of Science and Technology Austria, 2025.","short":"R. Sett, Quantum Remote Sensing and Non-Equilibrium Phase Transitions in the Microwave Regime, Institute of Science and Technology Austria, 2025.","chicago":"Sett, Riya. “Quantum Remote Sensing and Non-Equilibrium Phase Transitions in the Microwave Regime.” Institute of Science and Technology Austria, 2025. <a href=\"https://doi.org/10.15479/AT-ISTA-19533\">https://doi.org/10.15479/AT-ISTA-19533</a>."},"tmp":{"image":"/images/cc_by.png","short":"CC BY (4.0)","name":"Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)","legal_code_url":"https://creativecommons.org/licenses/by/4.0/legalcode"},"doi":"10.15479/AT-ISTA-19533","author":[{"orcid":"0000-0001-7641-8348","last_name":"Sett","first_name":"Riya","id":"2E6D040E-F248-11E8-B48F-1D18A9856A87","full_name":"Sett, Riya"}],"title":"Quantum remote sensing and non-equilibrium phase transitions in the microwave regime","date_updated":"2026-08-12T08:45:39Z","day":"1","file_date_updated":"2025-10-11T22:30:02Z","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.","related_material":{"record":[{"id":"18978","relation":"research_data","status":"public"},{"status":"public","id":"19280","relation":"part_of_dissertation"},{"relation":"part_of_dissertation","id":"17183","status":"public"},{"relation":"part_of_dissertation","id":"13117","status":"public"}]},"publication_identifier":{"issn":["2663-337X"]},"OA_place":"publisher"},{"page":"3401-3411","oa":1,"type":"journal_article","keyword":["quantum optics","free electrons","single photon nonlinearity","electron-photon interaction"],"article_processing_charge":"No","year":"2024","publication_status":"published","date_published":"2024-07-29T00:00:00Z","user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","publisher":"American Chemical Society","date_created":"2026-03-30T12:22:47Z","abstract":[{"lang":"eng","text":"A central challenge in the emerging field of free-electron quantum optics is to achieve strong quantum interaction and single-photon nonlinearity between a flying free electron and a photonic mode. Existing schemes are intrinsically limited by electron diffraction, which puts an upper bound on the interaction length and, therefore, on the strength of quantum coupling and nonlinearity. Here, we propose “free-electron fibers”: effectively one-dimensional photonic systems where free electrons copropagate with two guided modes. The first mode applies a ponderomotive trap to the free electron, removing the limitations due to electron diffraction. The second mode strongly couples to the guided free electron with an enhanced coupling that is orders of magnitude larger than previous designs. The extended interaction lengths enabled by our scheme allow for strong single-photon nonlinearities mediated by free electrons. We predict novel quantum effects in our system such as deterministic single-photon emission and nonlinear multimode dynamics. Our proposal paves the way toward the realization of heralded macroscopic nonclassical light generation, deterministic single-photon sources, and quantum gates controlled by free-electron–photon interactions."}],"intvolume":"        11","OA_type":"green","language":[{"iso":"eng"}],"issue":"8","status":"public","month":"07","ddc":["530"],"publication":"ACS Photonics","arxiv":1,"publication_identifier":{"eissn":["2330-4022"]},"article_type":"original","day":"29","external_id":{"arxiv":["2403.13071"]},"OA_place":"repository","author":[{"full_name":"Karnieli, Aviv","last_name":"Karnieli","first_name":"Aviv"},{"id":"e2e68fc9-6505-11ef-a541-eb4e72cc3e82","full_name":"Roques-Carmes, Charles","first_name":"Charles","last_name":"Roques-Carmes"},{"last_name":"Rivera","first_name":"Nicholas","full_name":"Rivera, Nicholas"},{"last_name":"Fan","first_name":"Shanhui","full_name":"Fan, Shanhui"}],"date_updated":"2026-04-27T10:30:37Z","title":"Strong coupling and single-photon nonlinearity in free-electron quantum optics","volume":11,"scopus_import":"1","citation":{"ieee":"A. Karnieli, C. Roques-Carmes, N. Rivera, and S. Fan, “Strong coupling and single-photon nonlinearity in free-electron quantum optics,” <i>ACS Photonics</i>, vol. 11, no. 8. American Chemical Society, pp. 3401–3411, 2024.","mla":"Karnieli, Aviv, et al. “Strong Coupling and Single-Photon Nonlinearity in Free-Electron Quantum Optics.” <i>ACS Photonics</i>, vol. 11, no. 8, American Chemical Society, 2024, pp. 3401–11, doi:<a href=\"https://doi.org/10.1021/acsphotonics.4c00908\">10.1021/acsphotonics.4c00908</a>.","apa":"Karnieli, A., Roques-Carmes, C., Rivera, N., &#38; Fan, S. (2024). Strong coupling and single-photon nonlinearity in free-electron quantum optics. <i>ACS Photonics</i>. American Chemical Society. <a href=\"https://doi.org/10.1021/acsphotonics.4c00908\">https://doi.org/10.1021/acsphotonics.4c00908</a>","ama":"Karnieli A, Roques-Carmes C, Rivera N, Fan S. 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