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Decoherence and the Puzzle of Quantum Brownian Motion in a Gas

Lajos Diósi

arXiv:2010.03547Fundamental theories of physicsJan 1, 20221 citation

The Brownian Motion in an Ideal Quantum Qas

Chi-Chun Zhou, Zhang, Ping, Wu-Sheng Dai

A Brownian particle in an ideal quantum gas is considered. The mean square displacement (MSD) is derived. The Bose-Einstein or Fermi-Dirac distribution, other than the Maxwell-Boltzmann distribution, provides a different stochastic force compared with the classical Brownian motion. The MSD, which depends on the thermal wavelength and the density of medium particles, reflects the quantum effect on the Brownian particle explicitly. The result shows that the MSD in an ideal Bose gas is shorter than that in a Fermi gas. The behavior of the quantum Brownian particle recovers the classical Brownian particle as the temperature raises. At low temperatures, the quantum effect becomes obvious. For example, there is a random motion of the Brownian particle due to the fermionic exchange interaction even the temperature is near the absolute zero.A Brownian particle in an ideal quantum gas is considered. The mean square displacement (MSD) is derived. The Bose-Einstein or Fermi-Dirac distribution, other than the Maxwell-Boltzmann distribution, provides a different stochastic force compared with the classical Brownian motion. The MSD, which depends on the thermal wavelength and the density of medium particles, reflects the quantum effect on the Brownian particle explicitly. The result shows that the MSD in an ideal Bose gas is shorter than that in a Fermi gas. The behavior of the quantum Brownian particle recovers the classical Brownian particle as the temperature raises. At low temperatures, the quantum effect becomes obvious. For example, there is a random motion of the Brownian particle due to the fermionic exchange interaction even the temperature is near the absolute zero.

arXiv:2003.05288Mar 9, 20200 citations

Brownian motion of quantum particles

V. I. Mel'Nikov, S. V. Meshkov

Aug 1, 19831 citation

From nonequilibrium quantum Brownian motion to impurity dynamics in one-dimensional quantum liquids

Julius Bonart, Leticia F. Cugliandolo

Impurity motion in one-dimensional ultracold quantum liquids confined in an optical trap has attracted much interest recently. As a step towards its full understanding, we construct a generating functional from which we derive the position nonequilibrium correlation function of a quantum Brownian particle with general Gaussian nonfactorizing initial conditions. We investigate the slow dynamics of a particle confined in a harmonic potential after a position measurement; the rapid relaxation of a particle trapped in a harmonic potential after a quantum quench realized as a sudden change in the potential parameters; and the evolution of an impurity in contact with a one-dimensional bosonic quantum gas. We argue that such an impurity--Luttinger-liquid system, which has been recently realized experimentally, admits a simple modeling as quantum Brownian motion in a super-Ohmic bath.Impurity motion in one-dimensional ultracold quantum liquids confined in an optical trap has attracted much interest recently. As a step towards its full understanding, we construct a generating functional from which we derive the position nonequilibrium correlation function of a quantum Brownian particle with general Gaussian nonfactorizing initial conditions. We investigate the slow dynamics of a particle confined in a harmonic potential after a position measurement; the rapid relaxation of a particle trapped in a harmonic potential after a quantum quench realized as a sudden change in the potential parameters; and the evolution of an impurity in contact with a one-dimensional bosonic quantum gas. We argue that such an impurity--Luttinger-liquid system, which has been recently realized experimentally, admits a simple modeling as quantum Brownian motion in a super-Ohmic bath.

arXiv:1203.5273Physical Review AAug 30, 201238 citations

Brownian motion of a quantum particle

Boris B. Kadomtsev, Михаил Борисович Кадомцев

Physics Letters AJun 1, 19973 citations

Quantum Master Equation of a Particle in a Gas Environment

Lajos Diósi

The reduced dynamics of a Brownian particle is discussed in single collision approach valid typically in dilute-gas environments. Our main purpose is a consistent account of quantum friction caused by local environmental interactions. We derive a Lindblad master equation whose generators are calculated from the differential cross-section of single collisions between the Brownian and the gas particles, respectively. The existence of thermal equilibrium for the Brownian particle's state ρ is proved. Master equations proposed earlier are shown to be particular cases of our one.The reduced dynamics of a Brownian particle is discussed in single collision approach valid typically in dilute-gas environments. Our main purpose is a consistent account of quantum friction caused by local environmental interactions. We derive a Lindblad master equation whose generators are calculated from the differential cross-section of single collisions between the Brownian and the gas particles, respectively. The existence of thermal equilibrium for the Brownian particle's state ρ is proved. Master equations proposed earlier are shown to be particular cases of our one.

arXiv:gr-qc/9403046Europhysics Letters (EPL)Apr 10, 1995108 citations

Relaxation dynamics of a quantum Brownian particle in an ideal gas

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