{"oa":1,"status":"public","author":[{"last_name":"Janik","id":"396A1950-F248-11E8-B48F-1D18A9856A87","full_name":"Janik, Marian","first_name":"Marian","orcid":"0009-0003-9037-8831"}],"acknowledged_ssus":[{"_id":"M-Shop"},{"_id":"NanoFab"}],"ddc":["539"],"date_updated":"2025-09-11T10:20:07Z","publisher":"Institute of Science and Technology Austria","file_date_updated":"2025-05-23T22:30:09Z","related_material":{"record":[{"relation":"part_of_dissertation","id":"18144","status":"public"}]},"type":"dissertation","date_created":"2024-09-23T17:25:43Z","day":"24","page":"164","has_accepted_license":"1","month":"09","supervisor":[{"orcid":"0000-0001-8342-202X","first_name":"Georgios","id":"38DB5788-F248-11E8-B48F-1D18A9856A87","last_name":"Katsaros","full_name":"Katsaros, Georgios"}],"user_id":"8b945eb4-e2f2-11eb-945a-df72226e66a9","doi":"10.15479/at:ista:18129","abstract":[{"text":"State-of-the-art quantum computers, with roughly a thousand qubits, face a crucial technological challenge of scaling up. Spins confined in quantum dots (QDs) are a promising candidate\r\nfor qubits due to their long coherence, tunability, control, and readout. However, their natural\r\ncoupling is the short-ranged (∼ 100 nm) exchange interaction, limited to nearest neighbours.\r\nLong-ranged (∼ 1 mm) qubit interactions mediated by a photon could be engineered through a\r\ncoherent spin-photon coupling. Achieving a strong coupling to a photon is inherently challenging in QDs due to the small dipole moment of the confined charge. However, the potential of\r\nhigh-impedance resonators to compensate for this has gained significant attention in the past\r\ndecade. Nevertheless, previous QD circuit quantum electrodynamics implementations have not\r\nexceeded the impedance of ∼ 3.8 kΩ, leaving opportunities for significant improvement. The\r\nlarge kinetic inductance of granular aluminium (grAl) could provide an order-of-magnitude\r\nenhancement. However, fully exploiting the potential of disordered or granular superconductors\r\nis challenging as their impedances close to the superconductor-to-insulator transition are\r\ndifficult to control reproducibly. We report on the realization of a wireless ohmmeter which\r\nallows in situ resistance measurements during film deposition and, therefore, indirect control\r\nof the kinetic inductance of grAl films. This allows us to reproducibly fabricate resonators\r\nwith characteristic impedance exceeding the resistance quantum, even reaching 22.3 kW, due\r\nto the large sheet kinetic inductance of up to 3 nH □−1\r\n. By integrating an 8 kW resonator\r\nwith a germanium double QD, we demonstrate a strong charge-photon coupling with the\r\nhighest rate reported, 566 MHz. The demonstrated method and grAl properties make these\r\nresonators suitable for boosting the spin-photon coupling strength, a crucial requirement for\r\nfast, high-fidelity, long-distance two-qubit gates.\r\n","lang":"eng"}],"date_published":"2024-09-24T00:00:00Z","year":"2024","publication_identifier":{"issn":["2663-337X"]},"citation":{"ama":"Janik M. Strong charge-photon coupling in Germanium enabled by granular aluminium superinductors. 2024. doi:<a href=\"https://doi.org/10.15479/at:ista:18129\">10.15479/at:ista:18129</a>","apa":"Janik, M. (2024). <i>Strong charge-photon coupling in Germanium enabled by granular aluminium superinductors</i>. Institute of Science and Technology Austria. <a href=\"https://doi.org/10.15479/at:ista:18129\">https://doi.org/10.15479/at:ista:18129</a>","ieee":"M. Janik, “Strong charge-photon coupling in Germanium enabled by granular aluminium superinductors,” Institute of Science and Technology Austria, 2024.","mla":"Janik, Marian. <i>Strong Charge-Photon Coupling in Germanium Enabled by Granular Aluminium Superinductors</i>. Institute of Science and Technology Austria, 2024, doi:<a href=\"https://doi.org/10.15479/at:ista:18129\">10.15479/at:ista:18129</a>.","short":"M. Janik, Strong Charge-Photon Coupling in Germanium Enabled by Granular Aluminium Superinductors, Institute of Science and Technology Austria, 2024.","chicago":"Janik, Marian. “Strong Charge-Photon Coupling in Germanium Enabled by Granular Aluminium Superinductors.” Institute of Science and Technology Austria, 2024. <a href=\"https://doi.org/10.15479/at:ista:18129\">https://doi.org/10.15479/at:ista:18129</a>.","ista":"Janik M. 2024. Strong charge-photon coupling in Germanium enabled by granular aluminium superinductors. Institute of Science and Technology Austria."},"title":"Strong charge-photon coupling in Germanium enabled by granular aluminium superinductors","tmp":{"image":"/images/cc_by.png","legal_code_url":"https://creativecommons.org/licenses/by/4.0/legalcode","short":"CC BY (4.0)","name":"Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)"},"_id":"18129","article_processing_charge":"No","corr_author":"1","alternative_title":["ISTA Thesis"],"degree_awarded":"PhD","language":[{"iso":"eng"}],"file":[{"access_level":"closed","file_id":"18130","creator":"mjanik","file_size":156207943,"relation":"source_file","date_updated":"2025-05-23T22:30:09Z","content_type":"application/x-zip-compressed","date_created":"2024-09-23T17:15:09Z","checksum":"dc15958f6400b5bdaa28bf58fc7a4056","file_name":"janik_thesis.zip","embargo_to":"open_access"},{"content_type":"application/pdf","date_updated":"2025-05-23T22:30:09Z","relation":"main_file","file_size":96195684,"creator":"mjanik","access_level":"open_access","file_id":"18131","embargo":"2025-05-23","file_name":"janik_thesis_pdfa.pdf","checksum":"74737aee285dc1f491643327350efe9c","date_created":"2024-09-23T17:15:30Z"}],"oa_version":"Published Version","department":[{"_id":"GradSch"},{"_id":"GeKa"}],"project":[{"grant_number":"I05060","_id":"c0977eea-5a5b-11eb-8a69-a862db0cf4d1","name":"High impedance circuit quantum electrodynamics with hole spins"},{"grant_number":"P36507","name":"Merging spin and superconducting qubits in planar Ge","_id":"bd8bd29e-d553-11ed-ba76-f0070d4b237a"},{"grant_number":"P32235","name":"Towards scalable hut wire quantum devices","call_identifier":"FWF","_id":"237B3DA4-32DE-11EA-91FC-C7463DDC885E"},{"grant_number":"101069515","name":"Integrated Germanium Quantum Technology","_id":"34c0acea-11ca-11ed-8bc3-8775e10fd452"},{"_id":"eb9b30ac-77a9-11ec-83b8-871f581d53d2","name":"Protected states of quantum matter"}],"publication_status":"published"}