Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:physics/9902037 · Journal of Physics B Atomic Molecular and Optical Physics

Quantum theory of dissipation of a harmonic oscillator coupled to a non-equilibrium bath; Wigner-Weisskopf decay and physical spectra

Jyotipratim Ray Chaudhuri, Bimalendu Deb, Gautam Gangopadhyay, Deb Shankar Ray

Published Sep 14, 1998• 7 citations
arXivHTMLPDF

Abstract

We extend the quantum theory of dissipation in the context of a system-reservoir model, where the reservoir in question is kept in a non-equilibrium condition. Based on a systematic separation of time scales involved in the dynamics, appropriate generalizations of the fluctuation-dissipation and Einstein's relations have been pointed out. We show that the Wigner-Weisskopf decay of the system mode results in a rate constant which, depending on the relaxation of a non-equilibrium bath, is dynamically modified. We also calculate the time-dependent spectra of a cavity mode with a suitable gain when the cavity is kept in contact with a non-equilibrium bath.

DOI
10.1088/0953-4075/31/17/011

Related papers

Quantum theory of dissipation of a harmonic oscillator coupled to a nonequilibrium bath: Wigner-Weisskopf decay and physical spectra

Chaudhuri, J R, Deb, B, Shankar, Ray D

We extend the quantum theory of dissipation in the context of system-reservoir model, where the reservoir in question is kept in a nonequilibrium condition. Based on a systematic separation of time scales involved in the dynamics, appropriate generalizations of the fluctuation-dissipation and Einstein's relations have been pointed out. We show that the Wigner-Weisskopf decay of the system mode results in a rate constant which depending on the relaxation of nonequilibrium bath is dynamically modified. We also calculate the time-dependent spectra of a cavity mode with a suitable gain when the cavity is kept in contact with a nonequilibrium bath.

•Jan 1, 1998•7 citations

Quantum dynamics of a harmonic oscillator in a non-equilibrium bath without the rotating wave approximation

Daeimohammad, Mohsen

The aim of this paper is to investigate dynamical properties of a harmonic oscillator coupled to a non-equilibrium bath without the rotating wave approximation. At first, we investigate the theory of this model and obtain the Heisenberg equations of motion for the oscillator and bath annihilation operators in the absence and in the presence of a rotating wave approximation. Then, we obtain the fluctuation and fluctuation-dissipation relations in the absence and in the presence of a rotating wave approximation for the non-equilibrium bath annihilation operator, respectively. After that, we study the decay of system modes using the Wigner-Weisskopf approximation. Finally, we calculate the time-dependent spectrum of a cavity field mode coupled to a non-equilibrium reservoir. We show that even under the condition in which the RWA is considered to be valid (weak interaction), there are significant effects of virtual-photon field on the diffusion coefficient, the energy density, line width and the shift frequency.

Iranian Journal of Physics Research•May 1, 2022•0 citations

Dissipation control in cavity QED with oscillating mode structures

I. E. Linington, B. M. Garraway

We demonstrate how a time-dependent dissipative environment may be used as a tool for controlling the quantum state of a two-level atom. In our model system the frequency and coupling strength associated with microscopic reservoir modes are modulated, while the principal features of the reservoir structure remain fixed in time. Physically, this may be achieved by containing a static atom-cavity system inside an oscillating external bath. We show that it is possible to dynamically decouple the atom from its environment, despite the fact that the two remain resonant at all times. This can lead to Markovian dynamics, even for a strong atom-bath coupling, as the atomic decay becomes inhibited into all but a few channels; the reservoir occupation spectrum consequently acquires a sideband structure, with peaks separated by the frequency of the environmental modulation. The reduction in the rate of spontaneous emission using this approach can be significantly greater than could be achieved with an oscillatory atom-bath detuning using the same parameters.

arXiv:0802.1199•Physical Review A•Mar 18, 2008•30 citations

Relaxation spectrum of quantum harmonic motion in the presence of nonlinear dissipative-diffusive couplings

Marcelo A. Despósito, E. Susana Hernández

We analyze the behavior of a damped quantum harmonic oscillator immersed in a heat bath with a nonlinear coupling. For this purpose, we construct a generalized master equation (GME) for the reduced density of the oscillator. We specialize the results for a quadratic coupling in the presence of a bosonic reservoir and an Ohmic dissipation model, analyzing the evolution equation for the mean value of the oscillator coordinate. In the asymptotic case we obtain a gain-loss master equation whose transition rates are polynomials in the number of quanta. No explicit solutions other than the equilibrium one can be written, since the standard methods do not apply. The equilibrium solution is investigated and the eigenvalues of the corresponding spectral problem are numerically computed to study the effect of the nonlinearity on the evolution of the system. By means of the Wigner transformation of the GME, we extract a third-order partial derivative equation that represents the semiclassical evolution of the damped oscillator. In the classical limit this is a nonlinear Fokker-Planck equation.

Physical Review A•Dec 1, 1992•5 citations

Dynamics of Open Quantum Systems I, Oscillation and Decay

Marco Merkli

We develop a framework to analyze the dynamics of a finite-dimensional quantum system S in contact with a reservoir R . The full, interacting SR dynamics is unitary. The reservoir has a stationary state but otherwise dissipative dynamics. We identify a main part of the full dynamics, which approximates it for small values of the SR coupling constant, uniformly for all times t≥0 . The main part consists of explicit oscillating and decaying parts. We show that the reduced system evolution is Markovian for all times. The technical novelty is a detailed analysis of the link between the dynamics and the spectral properties of the generator of the SR dynamics, based on Mourre theory. We allow for SR interactions with little regularity, meaning that the decay of the reservoir correlation function only needs to be polynomial in time, improving on the previously required exponential decay.In this work we distill the structural and technical ingredients causing the characteristic features of oscillation and decay of the SR dynamics. In the companion paper [27] we apply the formalism to the concrete case of an N -level system linearly coupled to a spatially infinitely extended thermal bath of non-interacting Bosons.

arXiv:2105.00015•Quantum•Jan 3, 2022•19 citations

Decoherence of a quantum magneto-oscillator: Effect of field-bath interaction

Koushik Mandal, Suraka Bhattacharjee, Supurna Sinha

We investigate the quantum dissipative dynamics of a charged magneto-oscillator(CMO) coupled to a heat bath of harmonic oscillators in the presence of an additional field-bath interaction. The problem is formulated within the framework of the generalized quantum Langevin equation, where the external confining potential modifies the random force correlations and the memory kernel of the environment, and the effective spring constant. Using the corresponding non-Markovian master equation, we examine the influence of the field-bath coupling on the temporal decay of the reduced density matrix of the system. We show that the additional interaction leads to an enhancement of the decoherence rate by altering the dissipative response of the bath. Thus our results shed light on the role of field-bath coupling in the quantum to classical transition of a CMO. The resulting fluctuation-dissipation relation is analyzed, and the position autocorrelation, position-velocity correlation and velocity autocorrelation are obtained explicitly. The dependence of these experimentally accessible quantities on the field-bath coupling parameter is discussed. We outline an experimental proposal for testing our theoretical predictions. The study sheds light on reservoir engineering which is central to quantum technologies.

quant-pharXiv:2607.11137•Jul 14, 2026•0 citations
We extend the quantum theory of dissipation in the context of a system-reservoir model, where the reservoir in question is kept in a non-equilibrium condition. Based on a systematic separation of time scales involved in the dynamics, appropriate generalizations of the fluctuation-dissipation and Einstein's relations have been pointed out. We show that the Wigner-Weisskopf decay of the system mode results in a rate constant which, depending on the relaxation of a non-equilibrium bath, is dynamically modified. We also calculate the time-dependent spectra of a cavity mode with a suitable gain when the cavity is kept in contact with a non-equilibrium bath.
We extend the quantum theory of dissipation in the context of system-reservoir model, where the reservoir in question is kept in a nonequilibrium condition. Based on a systematic separation of time scales involved in the dynamics, appropriate generalizations of the fluctuation-dissipation and Einstein's relations have been pointed out. We show that the Wigner-Weisskopf decay of the system mode results in a rate constant which depending on the relaxation of nonequilibrium bath is dynamically modified. We also calculate the time-dependent spectra of a cavity mode with a suitable gain when the cavity is kept in contact with a nonequilibrium bath.
The aim of this paper is to investigate dynamical properties of a harmonic oscillator coupled to a non-equilibrium bath without the rotating wave approximation. At first, we investigate the theory of this model and obtain the Heisenberg equations of motion for the oscillator and bath annihilation operators in the absence and in the presence of a rotating wave approximation. Then, we obtain the fluctuation and fluctuation-dissipation relations in the absence and in the presence of a rotating wave approximation for the non-equilibrium bath annihilation operator, respectively. After that, we study the decay of system modes using the Wigner-Weisskopf approximation. Finally, we calculate the time-dependent spectrum of a cavity field mode coupled to a non-equilibrium reservoir. We show that even under the condition in which the RWA is considered to be valid (weak interaction), there are significant effects of virtual-photon field on the diffusion coefficient, the energy density, line width and the shift frequency.
We demonstrate how a time-dependent dissipative environment may be used as a tool for controlling the quantum state of a two-level atom. In our model system the frequency and coupling strength associated with microscopic reservoir modes are modulated, while the principal features of the reservoir structure remain fixed in time. Physically, this may be achieved by containing a static atom-cavity system inside an oscillating external bath. We show that it is possible to dynamically decouple the atom from its environment, despite the fact that the two remain resonant at all times. This can lead to Markovian dynamics, even for a strong atom-bath coupling, as the atomic decay becomes inhibited into all but a few channels; the reservoir occupation spectrum consequently acquires a sideband structure, with peaks separated by the frequency of the environmental modulation. The reduction in the rate of spontaneous emission using this approach can be significantly greater than could be achieved with an oscillatory atom-bath detuning using the same parameters.
We analyze the behavior of a damped quantum harmonic oscillator immersed in a heat bath with a nonlinear coupling. For this purpose, we construct a generalized master equation (GME) for the reduced density of the oscillator. We specialize the results for a quadratic coupling in the presence of a bosonic reservoir and an Ohmic dissipation model, analyzing the evolution equation for the mean value of the oscillator coordinate. In the asymptotic case we obtain a gain-loss master equation whose transition rates are polynomials in the number of quanta. No explicit solutions other than the equilibrium one can be written, since the standard methods do not apply. The equilibrium solution is investigated and the eigenvalues of the corresponding spectral problem are numerically computed to study the effect of the nonlinearity on the evolution of the system. By means of the Wigner transformation of the GME, we extract a third-order partial derivative equation that represents the semiclassical evolution of the damped oscillator. In the classical limit this is a nonlinear Fokker-Planck equation.
We develop a framework to analyze the dynamics of a finite-dimensional quantum system S in contact with a reservoir R . The full, interacting SR dynamics is unitary. The reservoir has a stationary state but otherwise dissipative dynamics. We identify a main part of the full dynamics, which approximates it for small values of the SR coupling constant, uniformly for all times t≥0 . The main part consists of explicit oscillating and decaying parts. We show that the reduced system evolution is Markovian for all times. The technical novelty is a detailed analysis of the link between the dynamics and the spectral properties of the generator of the SR dynamics, based on Mourre theory. We allow for SR interactions with little regularity, meaning that the decay of the reservoir correlation function only needs to be polynomial in time, improving on the previously required exponential decay.In this work we distill the structural and technical ingredients causing the characteristic features of oscillation and decay of the SR dynamics. In the companion paper [27] we apply the formalism to the concrete case of an N -level system linearly coupled to a spatially infinitely extended thermal bath of non-interacting Bosons.
We investigate the quantum dissipative dynamics of a charged magneto-oscillator(CMO) coupled to a heat bath of harmonic oscillators in the presence of an additional field-bath interaction. The problem is formulated within the framework of the generalized quantum Langevin equation, where the external confining potential modifies the random force correlations and the memory kernel of the environment, and the effective spring constant. Using the corresponding non-Markovian master equation, we examine the influence of the field-bath coupling on the temporal decay of the reduced density matrix of the system. We show that the additional interaction leads to an enhancement of the decoherence rate by altering the dissipative response of the bath. Thus our results shed light on the role of field-bath coupling in the quantum to classical transition of a CMO. The resulting fluctuation-dissipation relation is analyzed, and the position autocorrelation, position-velocity correlation and velocity autocorrelation are obtained explicitly. The dependence of these experimentally accessible quantities on the field-bath coupling parameter is discussed. We outline an experimental proposal for testing our theoretical predictions. The study sheds light on reservoir engineering which is central to quantum technologies.