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[This is the unpublished supplemental information from 1989 to the paper: J.M. Deutsch, "Quantum statistical mechanics in a closed system." Phys. Rev. A, 43(4), 2046 (1991).] A closed quantum mechanical system does not necessarily give time…

Quantum Physics · Physics 2025-02-25 J. M. Deutsch

The density matrix yields probabilistic information about the outcome of measurements on a quantum system, but it does not distinguish between classical randomness in the preparation of the system and entanglement with its environment.…

Quantum Physics · Physics 2025-09-11 Julien Pinske , Klaus Mølmer

The estimation of the density matrix of a $k$-level quantum system is studied when the parametrization is given by the real and imaginary part of the entries and they are estimated by independent measurements. It is established that the…

Quantum Physics · Physics 2009-11-13 D. Petz , K. M. Hangos , A. Magyar

We investigate the effect of repeated measurement for quantum dynamics of the suppressed systems which classical counterparts exhibit chaos. The essential feature of such systems is the quantum localization phenomena strongly limiting…

Quantum Physics · Physics 2008-02-03 B. Kaulakys

In the long-time limit, an open quantum system coupled to a dissipative environment is believed to lose its coherence without driving or measurement. Counterintuitively, we provide a necessary condition on trapping the coherence of a…

Quantum Physics · Physics 2022-09-07 Jia-Ming Zhang , Bing Chen , Jun Jing

A general framework to describe a vast majority of biology-inspired systems is to model them as stochastic processes in which multiple couplings are in play at the same time. Molecular motors, chemical reaction networks, catalytic enzymes,…

Statistical Mechanics · Physics 2020-11-25 Daniel M. Busiello , Deepak Gupta , Amos Maritan

We describe the decoherence process induced on a two-level quantum system in direct interaction with a non-equilibrium environment. The non-equilibrium feature is represented by a non-stationary random function corresponding to the…

Quantum Physics · Physics 2015-06-15 Fernando C. Lombardo , Paula I. Villar

We study decoherence of two non-interacting qubits. The environment and its interaction with the qubits are modelled by random matrices. Decoherence, measured in terms of purity, is calculated in linear response approximation. Monte Carlo…

Quantum Physics · Physics 2007-11-22 C. Pineda , T. Gorin , T. H. Seligman

In this note we describe some results concerning non-relativistic quantum systems at positive temperature and density confined to macroscopically large regions of physical space which are under the influence of some local, time-dependent…

Mathematical Physics · Physics 2007-05-23 Jürg Fröhlich , Marco Merkli , Simon Schwarz , Daniel Ueltschi

We establish a link between metastability and a discrete time-crystalline phase in a periodically driven open quantum system. The mechanism we highlight requires neither the system to display any microscopic symmetry nor the presence of…

Statistical Mechanics · Physics 2019-01-10 F. M. Gambetta , F. Carollo , M. Marcuzzi , J. P. Garrahan , I. Lesanovsky

We study numerically and analytically the quench dynamics of isolated many-body quantum systems. Using full random matrices from the Gaussian orthogonal ensemble, we obtain analytical expressions for the evolution of the survival…

Statistical Mechanics · Physics 2018-03-07 E. J. Torres-Herrera , Antonio M. García-García , Lea F. Santos

Simultaneous decoherence of conjugate observables of an open quantum system leads to a classical statistical mechanical description with constant phase space probability density in terms of a uniform ensemble. We investigate a scenario…

Quantum Physics · Physics 2026-03-30 S. Adarsh , P. N. Bala Subramanian , Sreeraj T. P

A relationship between the time scales of quantum coherence loss and short-time solvent response for a solute/bath system is derived for a Gaussian wave packet approximation for the bath. Decoherence and solvent response times are shown to…

Quantum Physics · Physics 2009-10-31 Oleg V. Prezhdo , Peter J. Rossky

The effects of the measurement apparatus on quantum coherence are studied by considering a purely dephasing model of a qubit. The initial state is prepared from a thermal state of the whole system by performing a nonselective measurement on…

Quantum Physics · Physics 2021-12-22 Filippo Giraldi

We study the local relaxation of closed quantum systems through the relative entropy between the reduced density matrix and its long time limit. We show, using analytic arguments combined with numerical checks, that this relative entropy…

Statistical Mechanics · Physics 2025-10-29 Filiberto Ares , Colin Rylands , Pasquale Calabrese

We identify and describe unique early time behavior of a quantum system initially in a superposition, interacting with its environment. This behavior -- the copycat process -- occurs after the system begins to decohere, but before complete…

Quantum Physics · Physics 2024-05-28 Rose Baunach , Andreas Albrecht , Andrew Arrasmith

For quantum annealing, as opposed to circuit based quantum computing, the solution to a computational problem is encoded in the ground state of a quantum system. Therefore its susceptibility to environmental effects is a different but not…

Quantum Physics · Physics 2018-09-25 Tobias Chasseur , Stefan Kehrein , Frank K. Wilhelm

We consider the problem of measurement using the Lindblad equation, which allows the introduction of time in the interaction between the measured system and the measurement apparatus. We use analytic results, valid for weak…

We introduce a continuous time model of many-body quantum dynamics based on infinitesimal random unitary operations, combined with projective measurements. We consider purification dynamics in this model, where the system is initialized in…

Quantum Physics · Physics 2024-01-29 Sebastian Leontica , Max McGinley

Following a recent work (briefly reviewed below) we consider temporal fluctuations in the reduced density matrix elements for a coupled system involving a pair of kicked rotors as also one made up of a pair of Harper Hamiltonians. These…

Quantum Physics · Physics 2009-11-10 Sankhasubhra Nag , Gautam Ghosh , Avijit Lahiri