Van Vu Tan, Hasegawa Yoshihiko
Department of Information and Communication Engineering, Graduate School of Information Science and Technology, The University of Tokyo, Tokyo 113-8656, Japan.
Phys Rev Lett. 2021 Nov 5;127(19):190601. doi: 10.1103/PhysRevLett.127.190601.
We consider the thermal relaxation process of a quantum system attached to single or multiple reservoirs. Quantifying the degree of irreversibility by entropy production, we prove that the irreversibility of the thermal relaxation is lower bounded by a relative entropy between the unitarily evolved state and the final state. The bound characterizes the state discrepancy induced by the nonunitary dynamics, and thus reflects the dissipative nature of irreversibility. Intriguingly, the bound can be evaluated solely in terms of the initial and final states and the system Hamiltonian, thereby providing a feasible way to estimate entropy production without prior knowledge of the underlying coupling structure. This finding refines the second law of thermodynamics and reveals a universal feature of thermal relaxation processes.
我们考虑了与单个或多个热库相连的量子系统的热弛豫过程。通过熵产生来量化不可逆程度，我们证明热弛豫的不可逆性以幺正演化态与终态之间的相对熵为下界。该界限表征了由非幺正动力学引起的态差异，从而反映了不可逆性的耗散本质。有趣的是，该界限仅可根据初态和终态以及系统哈密顿量来评估，从而提供了一种在无需了解潜在耦合结构先验知识的情况下估计熵产生的可行方法。这一发现完善了热力学第二定律，并揭示了热弛豫过程的一个普遍特征。
