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A quantum mechanical system of two coupled rotors (particles constrained to move on a circle) is studied from an open quantum systems point of view. One of the rotors is integrated out and the reduced density operator of the other rotor is…

Quantum Physics · Physics 2025-05-21 V V Sreedhar , Ankit Yadav

An explicit demonstration is given of a harmonic oscillator in equilibrium approaching the equilibrium of a corresponding interacting system by coupling it to a thermal bath consisting of a continuum of harmonic oscillators.

Quantum Physics · Physics 2007-06-27 Vinay Ambegaokar

We construct model master equations for local quantum dissipation. The master equations are in the form of Lindblad generators, with imposed constraints that the dissipations be strictly linear (i.e. ohmic), isotropic and translationally…

Condensed Matter · Physics 2009-10-22 M. R. Gallis

To this day, von Neumann definition of entropy remains the most popular measure of quantum entanglement. Much of the literature on entanglement entropy, particularly in the context of field theory, has focused on isolating the UV…

Quantum Physics · Physics 2019-02-27 S. Mahesh Chandran , S. Shankaranarayanan

Based on the stabilizer formalism underlying Quantum Error Correction (QEC), the design of an original Lindblad master equation for the density operator of a quantum harmonic oscillator is proposed. This Lindblad dynamics stabilizes exactly…

The Lindblad master equation is a fundamental tool for describing the evolution of open quantum systems, but its computational complexity poses a significant challenge, especially for large systems. This article introduces a stochastic…

Quantum Physics · Physics 2025-04-04 Sayak Adhikari , Roi Baer

Applying the Milburn equation to describe intrinsic decoherence, we study the interaction of three-coupled quantum harmonic oscillators or quantized fields. We give an explicit solution for the complete equation, i.e., beyond the usual…

Quantum Physics · Physics 2023-03-08 Alejandro R. Urzúa , Héctor M. Moya-Cessa

We derive the exact action for a damped mechanical system ( and the special case of the linear oscillator) from the path integral formulation of the quantum Brownian motion problem developed by Schwinger and by Feynman and Vernon. The…

High Energy Physics - Theory · Physics 2015-06-26 Y. N. Srivastava , G. Vitiello , A. Widom

We investigate the quantum entanglement of systems of coupled harmonic oscillators on the basis of thermo-field dynamics (TFD). For coupled harmonic oscillators at equilibrium, the extended entanglement entropy is derived using the TFD…

Statistical Mechanics · Physics 2017-04-25 Koichi Nakagawa

By definition, the Kraus representation of a harmonic oscillator suffering from the environment effect, modeled as the amplitude damping or the phase damping, is directly given by a simple operator algebra solution. As examples and…

Quantum Physics · Physics 2009-08-03 Yu-xi Liu , Sahin Kaya Ozdemir , Adam Miranowicz , Nobuyuki Imoto

A nonlinear master equation is derived, reflecting properly the entropy of open quantum systems. In contrast to linear alternatives, its equilibrium solution is exactly the canonical Gibbs density matrix. The corresponding nonlinear…

Quantum Physics · Physics 2021-02-08 Roumen Tsekov

Specific nonequilibrium states of the quantum harmonic oscillator described by the Lindblad equation have been hereby suggested. This equation makes it possible to determine time-varying effects produced by statistical operator or…

General Physics · Physics 2013-02-25 Boris Bondarev

It is shown that the the quantum phase space distributions corresponding to a density operator $\rho$ can be expressed, in thermofield dynamics, as overlaps between the state $\mid \rho >$ and "thermal" coherent states. The usefulness of…

Quantum Physics · Physics 2008-11-26 S. Chaturvedi , V. Srinivasan , G. S. Agarwal

This preprint contains the English translation of the paper "Relaxation dynamics of a quantum chain of harmonic oscillators", which was published by the author in 1980 in the Ukrainian Physical Journal. Comments describing its motivations,…

Statistical Mechanics · Physics 2012-01-30 S. B. Rutkevich

The properties of an alternative definition of quantum entropy, based on Wigner functions, are discussed. Such definition emerges naturally from the Wigner representation of quantum mechanics, and can easily quantify the amount of…

Quantum Physics · Physics 2009-11-07 G. Manfredi , M. R. Feix

The work is devoted to the study of quantum integrable systems associated with quantum loop algebras. The recently obtained equation for the zero temperature inhomogeneous reduced density operator is analyzed. It is demonstrated that any…

Mathematical Physics · Physics 2020-04-07 Alexander V. Razumov

We consider a thermal quantum harmonic oscillator weakly coupled to a heat bath at a different temperature. We analytically study the quantum heat exchange statistics between the two systems using the quantum-optical master equation. We…

Quantum Physics · Physics 2018-11-14 Tobias Denzler , Eric Lutz

In the problem of entanglement there exist two different notions. One is the entanglement of a quantum state, characterizing the state structure. The other is entanglement production by quantum operators, describing the action of operators…

Quantum Physics · Physics 2019-05-22 V. I. Yukalov , E. P. Yukalova , V. A. Yurovsky

The Ullersma model for the damped harmonic oscillator is coupled to the quantised electromagnetic field. All material parameters and interaction strengths are allowed to depend on position. The ensuing Hamiltonian is expressed in terms of…

Quantum Physics · Physics 2018-08-16 A. J. van Wonderen , L. G. Suttorp

Based on a simple observation that a classical second order differential equation may be decomposed into a set of two first order equations, we introduce a Hamiltonian framework to quantize the damped systems. In particular, we analyze the…

High Energy Physics - Theory · Physics 2015-06-26 Chihong Chou