相互作用自旋系统中的量子储能与热-功转换
Quantum Energy Storage versus Heat-to-Work Conversion in an Interacting Spin System
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中文总结 AI 辅助
该研究以各向异性海森堡哈密顿量描述的两量子比特系统为工作介质，对比其作为量子电池和量子奥托热机的性能，发现偶极相互作用可提升量子电池储能能力却降低热机最大功，揭示二者互补性及自旋相互作用对量子能量转换的调控作用。
中文摘要 AI 辅助
我们研究了作为量子电池和量子奥托热机的相互作用两量子比特系统的能量与热力学性能。工作介质由各向异性海森堡哈密顿量描述，其补充了偶极相互作用、对称自旋-轨道相互作用和外磁场。在统一的微观框架内，我们首先分析了相干幺正充电协议，并通过功熵、反功熵、充电功率、存储容量和量子相干性的ℓ₁范数表征所得的储能性能，研究了偶极相互作用、温度和磁场对这些量的影响。随后，我们将同一工作介质用于量子奥托循环，研究了吸热量、放热量、净功和热力学效率作为磁场调制、偶极相互作用和温度偏置的函数。对两种协议的直接比较揭示了它们对偶极相互作用响应的显著差异：在所研究的参数范围内，增大偶极相互作用可显著提升量子电池的最大功熵和存储容量，但每个奥托循环提取的最大功会降低；奥托效率随偶极相互作用呈非单调依赖，且始终低于卡诺界限。这些结果表明，量子储能能力的提升并不一定意味着热-功转换的增强，我们的发现凸显了量子电池与量子热机的互补性质，并展示了如何在同一物理平台内利用微观自旋相互作用控制不同形式的量子能量转换。
英文摘要
We investigate the energetic and thermodynamic performance of an interacting two-qubit system serving as both a quantum battery and a quantum Otto heat engine. The working medium is described by an anisotropic Heisenberg Hamiltonian supplemented by a dipolar interaction, a symmetric spin--orbit interaction, and an external magnetic field. Within a unified microscopic framework, we first analyze a coherent unitary charging protocol and characterize the resulting energy-storage performance through the ergotropy, anti-ergotropy, charging power, storage capacity, and $\ell_1$-norm of quantum coherence. We investigate the effects of the dipolar interaction, temperature, and magnetic field on these quantities. We then employ the same working medium in a quantum Otto cycle and study the absorbed and released heat, net work, and thermodynamic efficiency as functions of the magnetic-field modulation, dipolar interaction, and temperature bias. A direct comparison between the two protocols reveals a pronounced contrast in their response to the dipolar interaction. In the investigated parameter regime, increasing the dipolar interaction substantially enhances the maximum ergotropy and storage capacity of the quantum battery, whereas the maximum work extracted per Otto cycle decreases. The Otto efficiency exhibits a nonmonotonic dependence on the dipolar interaction while remaining below the Carnot bound. These results demonstrate that an enhancement of quantum energy-storage capability does not necessarily imply an enhancement of heat-to-work conversion. Our findings highlight the complementary nature of quantum batteries and quantum heat engines and show how microscopic spin interactions can be used to control different forms of quantum energy conversion within the same physical platform.
