Strong hole-photon coupling in planar Ge for probing charge degree and strongly correlated states
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 (Z<sub>r</sub> = 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 g<sub>0</sub>/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.
Authors
- Stefano Calcaterra (ORCID: https://orcid.org/0009-0001-7543-8360)
- Georgios Katsaros (ORCID: https://orcid.org/0000-0001-8342-202X)
- Pasquale Scarlino (ORCID: https://orcid.org/0000-0002-4570-5958)
- Daniel Loss (ORCID: https://orcid.org/0000-0001-5176-3073)
- Wonjin Jang (ORCID: https://orcid.org/0000-0002-2791-4182)
- Stefano Bosco (ORCID: https://orcid.org/0000-0002-4035-9654)
- Franco De Palma
- Fabian Oppliger
- Giovanni Isella (ORCID: https://orcid.org/0000-0001-5951-7440)
- Marián Janík
Institutions
- Institute of Science and Technology Austria (AT)
- University of Basel (CH)
- QuTech (NL)
- École Polytechnique Fédérale de Lausanne (CH)
- Politecnico di Milano (IT)
- Delft University of Technology (NL)
Publication Details
- Journal
- Nature Communications
- Published
- 2024-11-23
- DOI
- https://doi.org/10.1038/s41467-024-54520-7
- Citations
- 20
- Primary Topic
- Quantum and electron transport phenomena
- Type
- article
- Field-Weighted Citation Impact
- 6.75
Funders
- National Science Foundation
- École Polytechnique Fédérale de Lausanne
- Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung
- Austrian Science Fund
- HORIZON EUROPE Framework Programme
- Staatssekretariat für Bildung, Forschung und Innovation