Cavity-QED enhancement of quantum entanglement and battery performance in double quantum dots
Abstract
We theoretically investigate quantum correlations and energy storage in a single-electron silicon double quantum dot (eDQD) coupled to a single-mode microwave cavity. The charge and spin degrees of freedom are hybridized by Rashba spin-orbit coupling (SOC), while the cavity interacts with the eDQD through spin-photon and charge-photon couplings. Using the reduced thermal density matrix, we characterize spin-charge entanglement by concurrence and quantum coherence by the l1 norm. At low temperature, the cavity strongly modifies the spin-charge correlations, producing distinct regimes of enhanced and suppressed entanglement. We identify a nonlinear crossover between an eDQD-dominated regime and a photon-dressed regime. This crossover is revealed independently by two signatures: a rapid change in the concurrence and the onset of finite photon occupation in the cavity. Its boundary exhibits a dominant Gc∝√Ω dependence and is robust against cavity Hilbert-space truncation. Beyond the Rashba coupling studied in [Ferreira et al., Phys. Rev. A 107, 052408 (2023)], we show that the cavity provides an additional tunable means of controlling quantum correlations and energy storage. We further characterize the eDQD as a quantum battery under coherent charging and evaluate its stored energy and ergotropy. The ergotropy varies markedly across a cavity-dressing crossover resembling that identified from entanglement, connecting cavity-induced modification of the dressed states to extractable work. Optimization over the charge-photon coupling reveals parameter-dependent optimal charging regimes and enhanced maximum ergotropy with increasing Rashba coupling. Our results establish cavity coupling and SOC as complementary controls of quantum correlations and extractable energy in semiconductor eDQD-cavity systems.
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BibTeX
@misc{zad2026cavityqed,
title = {{Cavity-QED enhancement of quantum entanglement and battery performance in double quantum dots}},
author = {Hamid Arian Zad and Usama Shoukat and Michal Jaščur and Hazrat Ali and Saeed Haddadi},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.37034},
eprint = {2609.37034},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.37034},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Cavity-QED enhancement of quantum entanglement and battery performance in double quantum dots
AU - Hamid Arian Zad
AU - Usama Shoukat
AU - Michal Jaščur
AU - Hazrat Ali
AU - Saeed Haddadi
PY - 2026
DA - 2026/09/29
PB - arXiv
DO - 10.48550/arxiv.2609.37034
UR - https://arxiv.org/abs/2609.37034
AB - We theoretically investigate quantum correlations and energy storage in a single-electron silicon double quantum dot (eDQD) coupled to a single-mode microwave cavity. The charge and spin degrees of freedom are hybridized by Rashba spin-orbit coupling (SOC), while the cavity interacts with the eDQD through spin-photon and charge-photon couplings. Using the reduced thermal density matrix, we characterize spin-charge entanglement by concurrence and quantum coherence by the l_1 norm. At low temperature, the cavity strongly modifies the spin-charge correlations, producing distinct regimes of enhanced and suppressed entanglement. We identify a nonlinear crossover between an eDQD-dominated regime and a photon-dressed regime. This crossover is revealed independently by two signatures: a rapid change in the concurrence and the onset of finite photon occupation in the cavity. Its boundary exhibits a dominant G_c∝√Ω dependence and is robust against cavity Hilbert-space truncation. Beyond the Rashba coupling studied in [Ferreira et al., Phys. Rev. A 107, 052408 (2023)], we show that the cavity provides an additional tunable means of controlling quantum correlations and energy storage. We further characterize the eDQD as a quantum battery under coherent charging and evaluate its stored energy and ergotropy. The ergotropy varies markedly across a cavity-dressing crossover resembling that identified from entanglement, connecting cavity-induced modification of the dressed states to extractable work. Optimization over the charge-photon coupling reveals parameter-dependent optimal charging regimes and enhanced maximum ergotropy with increasing Rashba coupling. Our results establish cavity coupling and SOC as complementary controls of quantum correlations and extractable energy in semiconductor eDQD-cavity systems.
ER -