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An exact method to compute the entire equilibrium reduced density matrix for systems characterized by a system-bath Hamiltonian is presented. The approach is based upon a stochastic unraveling of the influence functional that appears in the…

Mesoscale and Nanoscale Physics · Physics 2015-06-04 Jeremy M. Moix , Yang Zhao , Jianshu Cao

This paper describes the dynamics of a quantum two-level system (qubit) under the influence of an environment modeled by an ensemble of random matrices. In distinction to earlier work, we consider here separable couplings and focus on a…

Quantum Physics · Physics 2015-06-19 M. Carrera , T. Gorin , T. H. Seligman

In this review, we discuss the decoherence and thermalization of a quantum spin system interacting with a spin bath environment, by numerically solving the time-dependent Schr\"{o}dinger equation of the whole system. The effects of the…

Quantum Physics · Physics 2010-05-27 Shengjun Yuan

We consider the dynamics of an arbitrary quantum system coupled to a large arbitrary and fully quantum mechanical environment through a random interaction. We establish analytically and check numerically the typicality of this dynamics, in…

Quantum Physics · Physics 2017-07-26 Grégoire Ithier , Florent Benaych-Georges

We extend the Runge-Gross theorem for a very general class of Markovian and non-Markovian open quantum systems under weak assumptions about the nature of the bath and its coupling to the system. We show that for Kohn-Sham (KS)…

Materials Science · Physics 2011-02-09 Joel Yuen-Zhou , David G. Tempel , César Rodríguez-Rosario , Alán Aspuru-Guzik

We present a quantum information-inspired framework for analyzing complex systems through multivariate time series. In this approach the system's state is encoded into a density matrix, providing a compact representation of higher-order…

Chaotic Dynamics · Physics 2025-12-17 Parsa Kafashi , Mozhgan Orujlu

With a choice of boundary conditions for solutions of the Schr\"odinger equation, state vectors and density operators even for closed systems evolve asymmetrically in time. For open systems, standard quantum mechanics consequently predicts…

Quantum Physics · Physics 2010-05-25 P. W. Bryant

A generalized formal framework for decoherence, that can be used both in open and closed quantum systems, is sketched. In this context, the relationship between the decoherence of a closed system and the decoherence of its subsystems is…

Quantum Physics · Physics 2007-05-23 Mario Castagnino , Roberto Laura , Olimpia Lombardi

We study the influence of the preparation of an open quantum system on its reduced time evolution. In contrast to the frequently considered case of an initial preparation where the total density matrix factorizes into a product of a system…

Quantum Physics · Physics 2009-11-10 Karen M. Fonseca Romero , Peter Talkner , Peter Hänggi

A general theoretical framework for decoherence is proposed, which encompasses formalisms originally devised to deal just with open or with closed systems. The conditions for decoherence are clearly stated and the relaxation and decoherence…

Quantum Physics · Physics 2009-10-30 Mario Castagnino , Sebastian Fortin , Roberto Laura , Olimpia Lombardi

A key lesson of the decoherence program is that information flowing out from an open system is stored in the quantum state of the surroundings. Simultaneously, quantum measurement theory shows that the evolution of any open system when its…

Quantum Physics · Physics 2012-01-27 Juan Diego Urbina , Walter T. Strunz , Carlos Viviescas

Generalized Gibbs ensembles have been used as powerful tools to describe the steady state of integrable many-particle quantum systems after a sudden change of the Hamiltonian. Here we demonstrate numerically, that they can be used for a…

Strongly Correlated Electrons · Physics 2018-05-02 Florian Lange , Zala Lenarčič , Achim Rosch

A random matrix theory approach is applied in order to analyze the localization properties of local spectral density for a generic system of coupled quantum states with strong static imperfection in the unperturbed energy levels. The system…

Quantum Physics · Physics 2009-11-07 V. S. Starovoitov

We extend the coupled-cluster method to correlated quantum dynamics of both closed and open systems at finite temperatures using the thermo-field formalism. The approach expresses the time-dependent density matrix in an exponential ansatz…

Quantum Physics · Physics 2019-10-23 Philip Shushkov , Thomas F. Miller

We consider the continuous quantum measurement of a two-level system, for example, a single-Cooper-pair box measured by a single-electron transistor or a double-quantum dot measured by a quantum point contact. While the approach most…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 Alexander N. Korotkov

In many physical situations the behavior of a quantum system is affected by interaction with a larger environment. We develop, using the method of influence functional, how to deduce the density matrix of the quantum system incorporating…

High Energy Physics - Phenomenology · Physics 2009-10-28 M. Hotta , I. Joichi , Sh. Matsumoto , M. Yoshimura

Time crystals are genuinely non-equilibrium quantum phases of matter that break time-translational symmetry. While in non-equilibrium closed systems time crystals have been experimentally realized, it remains an open question whether or not…

Quantum Physics · Physics 2020-05-27 Andreu Riera-Campeny , Maria Moreno-Cardoner , Anna Sanpera

The nonequilibrium dynamics in chaotic quantum systems denies a fully understanding up to now, even if thermalization in the long-time asymptotic state has been explained by the eigenstate thermalization hypothesis which assumes a universal…

Statistical Mechanics · Physics 2020-12-08 Xinxin Yang , Pei Wang

We study the decoherence and thermalization dynamics of a nanoscale system coupled nonperturbatively to a fully quantum-mechanical bath. The system is prepared out of equilibrium in a pure state of the complete system. We propose a random…

Statistical Mechanics · Physics 2013-09-30 S. Genway , A. F. Ho , D. K. K. Lee

The paper addresses the problem of relaxation of open quantum systems. Using the path integral methods we found an analytical expression for time-dependent density matrix of two coupled quantum oscillators interacting with different baths…

Quantum Physics · Physics 2014-12-16 Illarion Dorofeyev