Heavy-Hole--Light-Hole Mixing and Spin--Photon Coupling in Germanium Flopping-Mode Qubits
Abstract
Intrinsic spin--orbit interaction in germanium provides electrically active flopping-mode qubits without requiring magnetic-field gradients to generate spin--charge hybridization. We study double quantum dots (DQDs) with a multiband Luttinger--Kohn framework that retains heavy-hole (HH) and light-hole (LH) states on equal footing. Modeling vertical confinement with a finite confinement potential along the growth direction brings selected subbands into a regime of appreciable HH--LH mixing. This admixture activates electric-dipole spin-coupling through LH--LH and LH--HH transitions, complementing the conventional HH--HH pseudospin-flip resonance. For the parameter sets considered, these additional channels can produce larger spin--photon figures of merit than the HH--HH transition. HH--LH mixing thus supplies a tunable ingredient for qubit--cavity coupling in germanium hole-spin qubits and extends the operating regimes available to circuit-QED architectures.
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BibTeX
@misc{reinagalvez2026heavyholelighthole,
title = {{Heavy-Hole--Light-Hole Mixing and Spin--Photon Coupling in Germanium Flopping-Mode Qubits}},
author = {Jose Reina-Gálvez and Guido Burkard},
howpublished = {arXiv},
year = {2026},
month = aug,
doi = {10.48550/arxiv.2608.29325},
eprint = {2608.29325},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2608.29325},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Heavy-Hole--Light-Hole Mixing and Spin--Photon Coupling in Germanium Flopping-Mode Qubits
AU - Jose Reina-Gálvez
AU - Guido Burkard
PY - 2026
DA - 2026/08/29
PB - arXiv
DO - 10.48550/arxiv.2608.29325
UR - https://arxiv.org/abs/2608.29325
AB - Intrinsic spin--orbit interaction in germanium provides electrically active flopping-mode qubits without requiring magnetic-field gradients to generate spin--charge hybridization. We study double quantum dots (DQDs) with a multiband Luttinger--Kohn framework that retains heavy-hole (HH) and light-hole (LH) states on equal footing. Modeling vertical confinement with a finite confinement potential along the growth direction brings selected subbands into a regime of appreciable HH--LH mixing. This admixture activates electric-dipole spin-coupling through LH--LH and LH--HH transitions, complementing the conventional HH--HH pseudospin-flip resonance. For the parameter sets considered, these additional channels can produce larger spin--photon figures of merit than the HH--HH transition. HH--LH mixing thus supplies a tunable ingredient for qubit--cavity coupling in germanium hole-spin qubits and extends the operating regimes available to circuit-QED architectures.
ER -