Wu Wei, An Jun-Hong
Key Laboratory of Quantum Theory and Applications of MoE, Lanzhou Center for Theoretical Physics and Key Laboratory of Theoretical Physics of Gansu Province, <a href="https://ror.org/01mkqqe32">Lanzhou University</a>, Lanzhou 730000, China.
Phys Rev Lett. 2024 Aug 2;133(5):050401. doi: 10.1103/PhysRevLett.133.050401.
The nonequilibrium fluctuation relation is a cornerstone of quantum thermodynamics. It is widely believed that the system-bath heat exchange obeys the famous Jarzynski-Wójcik fluctuation theorem. However, this theorem is established in the Born-Markovian approximation under the weak-coupling condition. Via studying the energy exchange between a harmonic oscillator and its coupled bath in the non-Markovian dynamics, we establish a generalized quantum fluctuation theorem for energy exchange being valid for arbitrary coupling strength. The Jarzynski-Wójcik fluctuation theorem is recovered in the weak-coupling limit. We also find the average energy exchange exhibits rich nonequilibrium characteristics when different numbers of system-bath bound states are formed, which suggests a useful way to control the quantum heat. Deepening our understanding of the fluctuation relation in quantum thermodynamics, our result lays the foundation to design high-efficiency quantum heat engines.
非平衡涨落关系是量子热力学的基石。人们普遍认为系统与环境的热交换服从著名的雅津斯基 - 沃伊奇克涨落定理。然而，该定理是在弱耦合条件下的玻恩 - 马尔可夫近似中建立的。通过研究非马尔可夫动力学中一个谐振子与其耦合环境之间的能量交换，我们建立了一个对任意耦合强度都有效的能量交换广义量子涨落定理。在弱耦合极限下恢复了雅津斯基 - 沃伊奇克涨落定理。我们还发现，当形成不同数量的系统 - 环境束缚态时，平均能量交换呈现出丰富的非平衡特征，这为控制量子热提供了一种有用的方法。我们的结果加深了我们对量子热力学中涨落关系的理解，为设计高效量子热机奠定了基础。
