TY - JOUR

T1 - Thermal property in Brownian motion of a particle coupled to vacuum fluctuations

AU - Oshita, Naritaka

AU - Yamamoto, Kazuhiro

AU - Zhang, Sen

N1 - Copyright:
Copyright 2014 Elsevier B.V., All rights reserved.

PY - 2014/6/24

Y1 - 2014/6/24

N2 - We investigate Brownian motions of a particle coupled to vacuum fluctuations of a quantum field. The Unruh effect predicts that an observer in an accelerated motion sees the Minkowski vacuum as thermally excited. This addresses the problem of whether or not a thermal property appears in a perturbative random motion of a particle in an accelerated motion due to the coupling. We revisit this problem by solving the equation of motion of a particle coupled to vacuum fluctuations including the radiation reaction force. We compute a Fourier integral for the variance of the random velocity in a rigorous manner. Similarly, we consider a particle coupled to vacuum fluctuations in de Sitter spacetime motivated by the argument that an observer in de Sitter spacetime sees the Bunch-Davies vacuum as a thermally excited state with the Gibbons-Hawking temperature. Our investigation clarifies the condition that the energy equipartition relation arises in the Brownian motions of a particle.

AB - We investigate Brownian motions of a particle coupled to vacuum fluctuations of a quantum field. The Unruh effect predicts that an observer in an accelerated motion sees the Minkowski vacuum as thermally excited. This addresses the problem of whether or not a thermal property appears in a perturbative random motion of a particle in an accelerated motion due to the coupling. We revisit this problem by solving the equation of motion of a particle coupled to vacuum fluctuations including the radiation reaction force. We compute a Fourier integral for the variance of the random velocity in a rigorous manner. Similarly, we consider a particle coupled to vacuum fluctuations in de Sitter spacetime motivated by the argument that an observer in de Sitter spacetime sees the Bunch-Davies vacuum as a thermally excited state with the Gibbons-Hawking temperature. Our investigation clarifies the condition that the energy equipartition relation arises in the Brownian motions of a particle.

UR - http://www.scopus.com/inward/record.url?scp=84903649589&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84903649589&partnerID=8YFLogxK

U2 - 10.1103/PhysRevD.89.124028

DO - 10.1103/PhysRevD.89.124028

M3 - Article

AN - SCOPUS:84903649589

VL - 89

JO - Physical Review D - Particles, Fields, Gravitation and Cosmology

JF - Physical Review D - Particles, Fields, Gravitation and Cosmology

SN - 1550-7998

IS - 12

M1 - 124028

ER -