Recently, in their attempt to construct steady state thermodynamics (SST), Komatsu, Nakagwa, Sasa, and Tasaki found an extension of the Clausius relation to nonequilibrium steady states in classical stochastic processes. Here we derive a quantum mechanical version of the extended Clausius relation. We consider a small system of interest attached to large systems which play the role of heat baths. By only using the genuine quantum dynamics, we realize a heat conducting nonequilibrium steady state in the small system. We study the response of the steady state when the parameters of the system are changed abruptly, and show that the extended Clausius relation, in which "heat" is replaced by the "excess heat", is valid when the temperature difference is small. Moreover we show that the entropy that appears in the relation is similar to von Neumann entropy but has an extra symmetrization with respect to time-reversal. We believe that the present work opens a new possibility in the study of nonequilibrium phenomena in quantum systems, and also confirms the robustness of the approach by Komtatsu et al.
Nonequilibrium Thermodynamics. Symmetric and Unique Formulation of the First Law, Statistical Definition of Heat and Work, Adiabatic Theorem and the Fate of the Clausius Inequality: A Microscopic View
We study entropy production in nanoscale devices, which are coupled to finite heat baths. This situation is of growing experimental relevance, but most theoretical approaches rely on a formulation of the second law valid only for infinite baths. We fix this problem by pointing out that already Clausius' paper from 1865 contains an adequate formulation of the second law for finite heat baths, which can be also rigorously derived from a microscopic quantum description. This Clausius' inequality shows that nonequilibrium processes are less irreversible than previously thought. We use it to correc…
Mesoscopic Nonequilibrium Thermodynamics of Single Macromolecules and Dynamic Entropy-Energy Compensation
基于随机动力学原理，我们对具有或不具有细致平衡的单个大分子在等温环境流体中的热力学行为给出了一个公理化的完整形式。通过细致平衡，新理论给出了大分子熵和自由能的介观、非平衡概括。介观能量和熵波动。当且仅当大分子处于热平衡时，熵产生的期望值为零，其中我们表明熵仍然波动，但自由能是常数。熵涨落a la L.D.朗道，精确地匹配的波动，在内能，这反过来又等于波动的热量耗散。作为Clausius经典结果的推广，在热平衡下，大分子熵和能量的动态涨落得到了精确补偿。对于系统的细致平衡，亥姆霍兹自由能被证明是潜在的Onsager的热力学力。
The review deals with a novel approach (MNEQT) to nonequilibrium thermodynamics (NEQT) that is based on the concept of internal equilibrium (IEQ) in an enlarged state space involving internal variables as additional state variables. The IEQ-macrostates are unique in the enlarged state space and have no memory just as EQ macrostates are in the EQ state space. The approach provides a clear strategy to identify the internal variables for any model through several examples. The MNEQT deals directly with system-intrinsic quantities, which are very useful as they fully describe irreversibility. Beca…
A First and Second Law for Nonequilibrium Thermodynamics: Maximum Entropy Derivation of the Fluctuation-Dissipation Theorem and Entropy Production Functionals
Describing open quantum systems far from equilibrium is challenging, in particular when the environment is mesoscopic, when it develops nonequilibrium features during the evolution, or when the memory effects cannot be disregarded. Here, we derive a master equation that explicitly accounts for system-bath correlations and includes, at a coarse-grained level, a dynamically evolving bath. Such a master equation applies to a wide variety of physical systems including those described by Random Matrix Theory or the Eigenstate Thermalization Hypothesis. We obtain a local detailed balance condition w…
Steady Periodic Shear Flow is Stable in Two Space Dimensions . Nonequilibrium Molecular Dynamics vs Navier-Stokes-Fourier Stability Theory -- A Comment on two Arxiv Contributions
