{"article_type":"original","quality_controlled":"1","publication":"Nature Communications","article_number":"10177","status":"public","abstract":[{"lang":"eng","text":"Semiconductor quantum dots (QDs) in planar germanium (Ge) heterostructures have emerged as front-runners for future hole-based quantum processors. Here, we present strong coupling between a hole charge qubit, defined in a double quantum dot (DQD) in planar Ge, and microwave photons in a high-impedance (Zr = 1.3 kΩ) resonator based on an array of superconducting quantum interference devices (SQUIDs). Our investigation reveals vacuum-Rabi splittings with coupling strengths up to g0/2π = 260 MHz, and a cooperativity of C ~ 100, dependent on DQD tuning. Furthermore, utilizing the frequency tunability of our resonator, we explore the quenched energy splitting associated with strong Coulomb correlation effects in Ge QDs. The observed enhanced coherence of the strongly correlated excited state signals the presence of distinct symmetries within related spin functions, serving as a precursor to the strong coupling between photons and spin-charge hybrid qubits in planar Ge. This work paves the way towards coherent quantum connections between remote hole qubits in planar Ge, required to scale up hole-based quantum processors."}],"intvolume":"        15","has_accepted_license":"1","type":"journal_article","external_id":{"pmid":["39580488"],"isi":["001362684200001"]},"doi":"10.1038/s41467-024-54520-7","oa_version":"Published Version","tmp":{"short":"CC BY (4.0)","legal_code_url":"https://creativecommons.org/licenses/by/4.0/legalcode","name":"Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)","image":"/images/cc_by.png"},"volume":15,"department":[{"_id":"GeKa"}],"date_published":"2024-12-01T00:00:00Z","OA_type":"gold","publisher":"Springer Nature","pmid":1,"publication_status":"published","day":"01","year":"2024","license":"https://creativecommons.org/licenses/by/4.0/","OA_place":"publisher","article_processing_charge":"Yes","month":"12","acknowledgement":"The authors thank Simone Frasca, Vincent Jouanny, Guillaume Beaulieu, Camille Roy, Dominic Dahinden, Davide Lombardo, Daniel Chrastina, and Siddhart Gautam for contributing to some cleanroom fabrication steps, the measurement setup, device simulations, data analysis, and for the useful discussions. P.S. acknowledges support from the Swiss National Science Foundation (SNSF) through the grants Ref. No. 200021 200418 and Ref. No. 206021_205335, and from the Swiss State Secretariat for Education, Research and Innovation (SERI) under contract number 01042765 SEFRI MB22.00081. W.J. acknowledges support from the EPFL QSE Postdoctoral Fellowship Grant. S.B., D.L., and P.S. acknowledge support from the NCCR Spin Qubit in Silicon (NCCR-SPIN) Grant No. 51NF40-180604. M.J., G.K., G.I., and S.C. acknowledge support from the Horizon Europe Project IGNITE ID 101070193. G.K. acknowledges support from the FWF via the P32235 and I05060 projects.","scopus_import":"1","oa":1,"_id":"18602","user_id":"317138e5-6ab7-11ef-aa6d-ffef3953e345","file_date_updated":"2024-12-03T11:00:15Z","citation":{"ieee":"F. De Palma <i>et al.</i>, “Strong hole-photon coupling in planar Ge for probing charge degree and strongly correlated states,” <i>Nature Communications</i>, vol. 15. Springer Nature, 2024.","ista":"De Palma F, Oppliger F, Jang W, Bosco S, Janik M, Calcaterra S, Katsaros G, Isella G, Loss D, Scarlino P. 2024. Strong hole-photon coupling in planar Ge for probing charge degree and strongly correlated states. Nature Communications. 15, 10177.","ama":"De Palma F, Oppliger F, Jang W, et al. Strong hole-photon coupling in planar Ge for probing charge degree and strongly correlated states. <i>Nature Communications</i>. 2024;15. doi:<a href=\"https://doi.org/10.1038/s41467-024-54520-7\">10.1038/s41467-024-54520-7</a>","short":"F. De Palma, F. Oppliger, W. Jang, S. Bosco, M. Janik, S. Calcaterra, G. Katsaros, G. Isella, D. Loss, P. Scarlino, Nature Communications 15 (2024).","mla":"De Palma, Franco, et al. “Strong Hole-Photon Coupling in Planar Ge for Probing Charge Degree and Strongly Correlated States.” <i>Nature Communications</i>, vol. 15, 10177, Springer Nature, 2024, doi:<a href=\"https://doi.org/10.1038/s41467-024-54520-7\">10.1038/s41467-024-54520-7</a>.","apa":"De Palma, F., Oppliger, F., Jang, W., Bosco, S., Janik, M., Calcaterra, S., … Scarlino, P. (2024). Strong hole-photon coupling in planar Ge for probing charge degree and strongly correlated states. <i>Nature Communications</i>. Springer Nature. <a href=\"https://doi.org/10.1038/s41467-024-54520-7\">https://doi.org/10.1038/s41467-024-54520-7</a>","chicago":"De Palma, Franco, Fabian Oppliger, Wonjin Jang, Stefano Bosco, Marian Janik, Stefano Calcaterra, Georgios Katsaros, Giovanni Isella, Daniel Loss, and Pasquale Scarlino. “Strong Hole-Photon Coupling in Planar Ge for Probing Charge Degree and Strongly Correlated States.” <i>Nature Communications</i>. Springer Nature, 2024. <a href=\"https://doi.org/10.1038/s41467-024-54520-7\">https://doi.org/10.1038/s41467-024-54520-7</a>."},"language":[{"iso":"eng"}],"DOAJ_listed":"1","isi":1,"title":"Strong hole-photon coupling in planar Ge for probing charge degree and strongly correlated states","project":[{"name":"Towards scalable hut wire quantum devices","call_identifier":"FWF","_id":"237B3DA4-32DE-11EA-91FC-C7463DDC885E","grant_number":"P32235"},{"name":"High impedance circuit quantum electrodynamics with hole spins","grant_number":"I05060","_id":"c0977eea-5a5b-11eb-8a69-a862db0cf4d1"}],"author":[{"first_name":"Franco","full_name":"De Palma, Franco","last_name":"De Palma"},{"first_name":"Fabian","full_name":"Oppliger, Fabian","last_name":"Oppliger"},{"last_name":"Jang","first_name":"Wonjin","full_name":"Jang, Wonjin"},{"full_name":"Bosco, Stefano","first_name":"Stefano","last_name":"Bosco"},{"last_name":"Janik","id":"396A1950-F248-11E8-B48F-1D18A9856A87","full_name":"Janik, Marian","first_name":"Marian","orcid":"0009-0003-9037-8831"},{"first_name":"Stefano","full_name":"Calcaterra, Stefano","last_name":"Calcaterra"},{"first_name":"Georgios","full_name":"Katsaros, Georgios","id":"38DB5788-F248-11E8-B48F-1D18A9856A87","last_name":"Katsaros","orcid":"0000-0001-8342-202X"},{"full_name":"Isella, Giovanni","first_name":"Giovanni","last_name":"Isella"},{"first_name":"Daniel","full_name":"Loss, Daniel","last_name":"Loss"},{"first_name":"Pasquale","full_name":"Scarlino, Pasquale","last_name":"Scarlino"}],"publication_identifier":{"eissn":["2041-1723"]},"date_updated":"2025-09-08T14:46:06Z","file":[{"content_type":"application/pdf","relation":"main_file","date_updated":"2024-12-03T11:00:15Z","success":1,"access_level":"open_access","checksum":"ef9f99a84089c388904cc8aa8d89c55a","file_size":5288092,"file_name":"2024_NatureComm_dePalma.pdf","creator":"dernst","file_id":"18611","date_created":"2024-12-03T11:00:15Z"}],"ddc":["530"],"date_created":"2024-12-01T23:01:53Z"}