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We present a systematic study of statistical mechanics for non-Hermitian quantum systems. Our work reveals that the stability of a non-Hermitian system necessitates the existence of a single path-dependent conserved quantity, which, in…

Statistical Mechanics · Physics 2023-12-04 Kui Cao , Su-Peng Kou

A non-Hermitian operator $H$ defined in a Hilbert space with inner product $\langle\cdot|\cdot\rangle$ may serve as the Hamiltonian for a unitary quantum system, if it is $\eta$-pseudo-Hermitian for a metric operator (positive-definite…

Quantum Physics · Physics 2020-06-05 Ali Mostafazadeh

Classical transport equations with probabilistic initial conditions can be viewed as quantum systems. In a discrete version they are probabilistic automata. The time-local probabilistic information is encoded in a classical wave function.…

Quantum Physics · Physics 2026-05-18 Christof Wetterich

In a recent work [10], Poulin and one of us presented a quantum algorithm for preparing thermal Gibbs states of interacting quantum systems. This algorithm is based on Grovers's technique for quantum state engineering, and its running time…

Computational Physics · Physics 2013-06-12 Chen-Fu Chiang , Pawel Wocjan

We treat the problem of the approach to thermal equilibrium by only resorting to quantum dynamics of an isolated macroscopic system. Inspired by the two important works in 2009 and in 1929, we have noted that a condition we call…

Quantum Physics · Physics 2015-03-13 Hal Tasaki

In this paper we address the problem to give a concrete support to the idea, originally stemming from Niels Bohr, that quantum mechanics must be rooted inside the physics of macroscopic systems. It is shown that, starting from the formalism…

Quantum Physics · Physics 2009-11-07 L. Lanz , O. Melsheimer , B. Vacchini

In the case of quantum systems interacting with multiple environments, the time-evolution of the reduced density matrix is described by the Liouvillian. For a variety of physical observables, the long-time limit or steady state solution is…

Quantum Physics · Physics 2022-01-05 Rodrigo A. Vargas-Hernández , Ricky T. Q. Chen , Kenneth A. Jung , Paul Brumer

In the context of unitary evolution of a generic quantum system interrupted at random times with non-unitary evolution due to interactions with either the external environment or a measuring apparatus, we adduce a general theoretical…

Quantum Physics · Physics 2022-05-10 Debraj Das , Sushanta Dattagupta , Shamik Gupta

Deterministic dynamical models are discussed which can be described in quantum mechanical terms. -- In particular, a local quantum field theory is presented which is a supersymmetric classical model. The Hilbert space approach of Koopman…

General Relativity and Quantum Cosmology · Physics 2015-06-25 Hans-Thomas Elze

We introduce a general statistical learning theory for processes that take as input a classical random variable and output a quantum state. Our setting is motivated by the practical situation in which one desires to learn a quantum process…

Quantum Physics · Physics 2025-02-27 Marco Fanizza , Yihui Quek , Matteo Rosati

The main purpose of these lectures is to discuss briefly recent methods of calculation of statistical properties of quantum eigenvalues for chaotic systems based on semi-classical trace formulas. Under the assumption that periodic orbit…

Chaotic Dynamics · Physics 2007-05-23 E. Bogomolny

A quantum mechanical explanation of the relaxation to equilibrium is shown for macroscopic systems for nonintegrable cases and numerically verified. The macroscopic system is initially in an equilibrium state, subsequently externally…

Statistical Mechanics · Physics 2015-05-28 Takaaki Monnai

We study classical Hamiltonian systems in which the intrinsic proper time evolution parameter is related through a probability distribution to the physical time, which is assumed to be discrete. In this way, a physical clock with discrete…

Quantum Physics · Physics 2007-05-23 H. -T. Elze

The statistical distribution for the case of an adiabatically isolated body was obtained in the framework of covariant quantum theory and Wick's rotation in the complex time plane. The covariant formulation of the mechanics of an isolated…

Statistical Mechanics · Physics 2022-05-17 Natalia Gorobey , Alexander Lukyanenko , A. V. Goltsev

Simulations are performed of a small quantum system interacting with a quantum environment. The system consists of various initial states of two harmonic oscillators coupled to give normal modes. The environment is "designed" by its level…

Statistical Mechanics · Physics 2015-06-15 George L. Barnes , Michael E. Kellman

A quasi-static process is realized in a purely quantum-mechanical model which is described by oscillator (or particle) systems having relative-phase interactions. Time development of a mixture of two oscillator (or particle) systems which…

Statistical Mechanics · Physics 2016-08-31 T. Kobayashi

Statistical mechanics is one of the most comprehensive theories in physics. From a boiling pot of water to the complex dynamics of quantum many-body systems it provides a successful connection between the microscopic dynamics of atoms and…

Quantum Gases · Physics 2016-10-06 B. Rauer , T. Schweigler , T. Langen , J. Schmiedmayer

If the von Neumann equation is modified by time dependent statistical weights, the time rate of entropy, the entropy exchange and production of a Schottky system are derived whose Hamiltonian does not contain the interaction with the…

Quantum Physics · Physics 2019-01-30 Wolfgang Muschik

Non-Markovian quantum processes exhibit different memory effects when measured in different ways; an unambiguous characterization of memory length requires accounting for the sequence of instruments applied to probe the system dynamics.…

Quantum Physics · Physics 2019-04-11 Philip Taranto , Simon Milz , Felix A. Pollock , Kavan Modi

We construct an effective commutative Schr\"odinger equation in Moyal space-time in $(1+1)$-dimension where both $t$ and $x$ are operator-valued and satisfy $\left[ \hat{t}, \hat{x} \right] = i \theta$. Beginning with a time-reparametrised…

Quantum Physics · Physics 2017-08-17 Partha Nandi , Sayan Kumar Pal , Aritra N Bose , Biswajit Chakraborty