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arXiv · 1403.5028

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

Naritaka Oshita·Kazuhiro Yamamoto·Sen Zhang
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Abstract

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 a thermal property appears in a perturbative random motion of a particle in an accelerated motion due to the coupling or not. 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.

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Naritaka Oshita, Kazuhiro Yamamoto, Sen Zhang. 2014-03-20. Thermal property in Brownian motion of a particle coupled to vacuum fluctuations. https://doi.org/10.1103/physrevd.89.124028

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