{"scopus_import":"1","quality_controlled":"1","date_published":"2023-10-20T00:00:00Z","volume":20,"article_number":"044054","publication_identifier":{"eissn":["2331-7019"]},"article_processing_charge":"No","title":"Compact vacuum-gap transmon qubits: Selective and sensitive probes for superconductor surface losses","intvolume":"        20","related_material":{"record":[{"id":"14520","status":"public","relation":"research_data"}]},"citation":{"ieee":"M. Zemlicka <i>et al.</i>, “Compact vacuum-gap transmon qubits: Selective and sensitive probes for superconductor surface losses,” <i>Physical Review Applied</i>, vol. 20, no. 4. American Physical Society, 2023.","apa":"Zemlicka, M., Redchenko, E., Peruzzo, M., Hassani, F., Trioni, A., Barzanjeh, S., &#38; Fink, J. M. (2023). Compact vacuum-gap transmon qubits: Selective and sensitive probes for superconductor surface losses. <i>Physical Review Applied</i>. American Physical Society. <a href=\"https://doi.org/10.1103/PhysRevApplied.20.044054\">https://doi.org/10.1103/PhysRevApplied.20.044054</a>","ama":"Zemlicka M, Redchenko E, Peruzzo M, et al. Compact vacuum-gap transmon qubits: Selective and sensitive probes for superconductor surface losses. <i>Physical Review Applied</i>. 2023;20(4). doi:<a href=\"https://doi.org/10.1103/PhysRevApplied.20.044054\">10.1103/PhysRevApplied.20.044054</a>","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.” <i>Physical Review Applied</i>. American Physical Society, 2023. <a href=\"https://doi.org/10.1103/PhysRevApplied.20.044054\">https://doi.org/10.1103/PhysRevApplied.20.044054</a>.","short":"M. Zemlicka, E. Redchenko, M. Peruzzo, F. Hassani, A. Trioni, S. Barzanjeh, J.M. Fink, Physical Review Applied 20 (2023).","mla":"Zemlicka, Martin, et al. “Compact Vacuum-Gap Transmon Qubits: Selective and Sensitive Probes for Superconductor Surface Losses.” <i>Physical Review Applied</i>, vol. 20, no. 4, 044054, American Physical Society, 2023, doi:<a href=\"https://doi.org/10.1103/PhysRevApplied.20.044054\">10.1103/PhysRevApplied.20.044054</a>.","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."},"main_file_link":[{"url":"https://arxiv.org/abs/2206.14104","open_access":"1"}],"acknowledged_ssus":[{"_id":"NanoFab"}],"day":"20","language":[{"iso":"eng"}],"author":[{"first_name":"Martin","last_name":"Zemlicka","full_name":"Zemlicka, Martin","id":"2DCF8DE6-F248-11E8-B48F-1D18A9856A87"},{"last_name":"Redchenko","first_name":"Elena","id":"2C21D6E8-F248-11E8-B48F-1D18A9856A87","full_name":"Redchenko, Elena"},{"last_name":"Peruzzo","orcid":"0000-0002-3415-4628","first_name":"Matilda","id":"3F920B30-F248-11E8-B48F-1D18A9856A87","full_name":"Peruzzo, Matilda"},{"full_name":"Hassani, Farid","id":"2AED110C-F248-11E8-B48F-1D18A9856A87","first_name":"Farid","orcid":"0000-0001-6937-5773","last_name":"Hassani"},{"last_name":"Trioni","first_name":"Andrea","id":"42F71B44-F248-11E8-B48F-1D18A9856A87","full_name":"Trioni, Andrea"},{"full_name":"Barzanjeh, Shabir","id":"2D25E1F6-F248-11E8-B48F-1D18A9856A87","first_name":"Shabir","orcid":"0000-0003-0415-1423","last_name":"Barzanjeh"},{"first_name":"Johannes M","last_name":"Fink","orcid":"0000-0001-8112-028X","full_name":"Fink, Johannes M","id":"4B591CBA-F248-11E8-B48F-1D18A9856A87"}],"year":"2023","oa":1,"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. "}],"_id":"14517","article_type":"original","status":"public","user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","type":"journal_article","date_updated":"2023-11-13T09:22:47Z","department":[{"_id":"JoFi"}],"oa_version":"Preprint","doi":"10.1103/PhysRevApplied.20.044054","project":[{"call_identifier":"FWF","grant_number":"F07105","_id":"26927A52-B435-11E9-9278-68D0E5697425","name":"Integrating superconducting quantum circuits"},{"name":"A Fiber Optic Transceiver for Superconducting Qubits","_id":"26336814-B435-11E9-9278-68D0E5697425","grant_number":"758053","call_identifier":"H2020"},{"_id":"eb9b30ac-77a9-11ec-83b8-871f581d53d2","name":"Protected states of quantum matter"},{"grant_number":"707438","call_identifier":"H2020","_id":"258047B6-B435-11E9-9278-68D0E5697425","name":"Microwave-to-Optical Quantum Link: Quantum Teleportation and Quantum Illumination with cavity Optomechanics SUPEREOM"},{"grant_number":"101080139","_id":"bdb7cfc1-d553-11ed-ba76-d2eaab167738","name":"Open Superconducting Quantum Computers (OpenSuperQPlus)"}],"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.","ec_funded":1,"issue":"4","publication":"Physical Review Applied","external_id":{"arxiv":["2206.14104"]},"publisher":"American Physical Society","publication_status":"published","date_created":"2023-11-12T23:00:55Z","month":"10"}