腔量子电动力学增强双量子点中的量子纠缠与电池性能
Cavity-QED enhancement of quantum entanglement and battery performance in double quantum dots
- P. J. Šafárik University（帕·约·沙法里克大学）
- Abbottabad University of Science and Technology（阿伯塔巴德科学与技术大学）
- Institute for Research in Fundamental Sciences (IPM)（基础科学研究所）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
本研究理论探讨了硅双量子点与微波腔耦合系统，发现腔可调控自旋-电荷纠缠，并提升量子电池的ergotropy，确立了腔耦合与SOC作为互补控制手段。
AI中文摘要：
我们在理论上研究了与单模微波腔耦合的单电子硅双量子点（eDQD）中的量子关联和能量存储。电荷和自旋自由度通过Rashba自旋轨道耦合（SOC）发生杂化，而腔通过自旋-光子耦合和电荷-光子耦合与eDQD相互作用。利用约化热密度矩阵，我们通过并发度表征自旋-电荷纠缠，并通过$l_1$范数表征量子相干性。在低温下，腔强烈改变自旋-电荷关联，产生增强和抑制纠缠的不同区域。我们识别出eDQD主导区域与光子修饰区域之间的非线性交叉。该交叉通过两个独立特征揭示：并发度的快速变化和腔内有限光子占据的出现。其边界表现出主导的$G_{\rm c}\propto\sqrt{\Omega}$依赖关系，并且对腔希尔伯特空间截断具有鲁棒性。超越[Ferreira等人，Phys. Rev. A 107, 052408 (2023)]中研究的Rashba耦合，我们表明腔提供了控制量子关联和能量存储的额外可调手段。我们进一步将eDQD表征为相干充电下的量子电池，并评估其存储能量和ergotropy。ergotropy在类似于从纠缠中识别出的腔修饰交叉中显著变化，将腔诱导的修饰态修改与可提取功联系起来。对电荷-光子耦合的优化揭示了参数依赖的最优充电区域，以及随着Rashba耦合增加而增强的最大ergotropy。我们的结果确立了腔耦合和SOC作为半导体eDQD-腔系统中量子关联和可提取能量的互补控制手段。
英文摘要：
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 $G_{\rm c}\propto\sqrtΩ$ 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.
