In order to understand the Landau-Lifshitz conjecture on the relationship between quantum measurements and the thermodynamic second law, we discuss the notion of ``diabatic'' and ``adiabatic'' forces exerted by the quantum object on the classical measurement apparatus. The notion of heat and work in measurements is made manifest in this approach, and the relationship between information entropy and thermodynamic entropy is explored.
Unified entropy production in finite quantum systems
Independent Researcher（独立研究者）；Department of Information and Communication Engineering, Graduate School of Information Science and Technology, The University of Tokyo（东京大学信息理工学系研究科信息通信工程学系）
Entropy production is a key quantity characterizing nonequilibrium systems. However, it can often be difficult to compute in practice, as it requires detailed information about the system and the dynamics it undergoes. This becomes even more difficult in the quantum domain, and if one is interested in generic nonequilibrium reservoirs, for which the standard thermal recipes no longer apply. In this paper, we derive an upper bound for the entropy production in terms of the entropy flux for a class of systems for which the flux is given in terms of a system's observable. Since currents are often…
Thermodynamic irreversibility is well characterized by the entropy production arising from non-equilibrium quantum processes. We show that the entropy production of a quantum system undergoing open-system dynamics can be formally split into a term that only depends on population unbalances, and one that is underpinned by quantum coherences. The population unbalances are found to contribute to both an entropy flux and an entropy production rate. The decoherence, on the other hand, contributes only to the entropy production rate. This allows us to identify a genuine quantum contribution to the e…
Fluctuation theorems allow one to make generalised statements about the behaviour of thermodynamic quantities in systems that are driven far from thermal equilibrium. In this article we use Crooks' fluctuation theorem to understand the entropy production of a continuously measured, zero-temperature quantum system; namely an optical cavity measured via homodyne detection. At zero temperature, if one uses the classical definition of inverse temperature $β$, then the entropy production becomes divergent. Our analysis shows that the entropy production can be well defined at zero temperature by con…
Local approach to entropy production in the nonequilibrium dynamics of open quantum systems
University of Freiburg（弗赖堡大学）；Institute of Physics, University of Freiburg（弗赖堡大学物理研究所）；EUCOR Centre for Quantum Science and Quantum Computing, University of Freiburg（弗赖堡大学EUCOR量子科学与量子计算中心）
We explore the notion of generated entropy in open quantum systems. We focus on the study of the discrete-time quantum walk on the line, from the entropy production perspective. We argue that the evolution of the coin can be modeled as an open two-level system that exchanges energy with the lattice at some effective temperature that depends on the initial state. The entropy balance shows that there is a positive entropy production during the evolution, in accordance with the second law of thermodynamics.
We develop a martingale theory to describe fluctuations of entropy production for open quantum systems in nonequilbrium steady states. Using the formalism of quantum jump trajectories, we identify a decomposition of entropy production into an exponential martingale and a purely quantum term, both obeying integral fluctuation theorems. An important consequence of this approach is the derivation of a set of genuine universal results for stopping-time and infimum statistics of stochastic entropy production. Finally we complement the general formalism with numerical simulations of a qubit system.
The second law of nonequilibrium thermodynamics within the open system paradigm (a small system coupled to one or multiple baths) is derived. This is done by showing positivity of entropy production for arbitrary Hamiltonian dynamics for a large class of initial states. Using the recently introduced notion of observational entropy, shortcomings of previous approaches are overcome. I apologize that the actual abstract of the manuscript is longer than the arXiv guidelines allow and therefore not displayed here.
The physics of driven-dissipative transitions is currently a topic of great interest, particularly in quantum optical systems. These transitions occur in systems kept out of equilibrium and are therefore characterized by a finite entropy production rate. However, very little is known about how the entropy production behaves around criticality and all of it is restricted to classical systems. Using quantum phase-space methods, we put forth a framework that allows for the complete characterization of the entropy production in driven-dissipative transitions. Our framework is tailored specifically…
We explore a recently introduced quantum thermodynamic entropy $S^Q_{univ}$ of a pure state of a composite system-environment computational "universe" with a simple system $\mathcal{S}$ coupled to a constant temperature bath $\mathcal{E}$. The principal focus is "excess entropy production" in which the quantum entropy change is greater than expected from the classical entropy-free energy relationship. We analyze this in terms of quantum spreading of time dependent states, and its interplay with the idea of a microcanonical shell. The entropy takes a basis-dependent Shannon information definiti…
Linear, irreversible thermodynamics predicts that the entropy production rate can become negative. We demonstrate this prediction for metals under AC-driving whose conductivity is well-described by the Drude-Sommerfeld model. We then show that these negative rates are fully compatible with stochastic thermodynamics, namely, that the entropy production does fulfill a fluctuation theorem. The analysis is concluded with the observation that the stochastic entropy production as defined by the surprisal or ignorance of the Shannon information does not agree with the phenomenological approach.
In this paper we study entropy production and transport of heat and matter in an 1D bipartite fermionic chain. Moreover, we input a phenomenological dephasing noise in order to show its effect on the dynamics of the system. Specially, it is shown the importance of such noise in the emergence of the entropy production. For the fluxes, analytical solutions are obtained using both Boltzmann and Fermi-Dirac distribuition. Finally, we show that a particular fluctuation theorem for energy and matter exchange is obeyed even in the presence of such noise.
We present a scheme to evaluate thermodynamic variables for a system coupled to a heat bath under a time-dependent external force using the quasi-static Helmholtz energy from the numerically "exact" hierarchical equations of motion (HEOM). We computed the entropy produced by a spin system strongly coupled to a non-Markovian heat bath for various temperatures. We showed that when changes to the external perturbation occurred sufficiently slowly, the system always reached thermal equilibrium. Thus, we calculated the Boltzmann entropy and the von Neumann entropy for an isothermal process, as well…
Interplay between Standard Quantum Detailed Balance and Thermodynamically Consistent Entropy Production
The University of Tokyo（东京大学）；RIKEN Hakubi Research Team, Pioneering Research Institute (PRI), RIKEN（理化学研究所前沿研究机构（PRI）Hakubi研究团队）；Universal Biology Institute, The University of Tokyo（东京大学全球生物学研究院）；Center for Gravitational Physics and Quantum Information, Yukawa Institute for Theoretical Physics, Kyoto University（京都大学汤川理论物理研究所引力物理与量子信息研究中心）；Department of Physics, Graduate School of Science, The University of Tokyo（东京大学理学研究科物理学系）
