TY - JOUR

T1 - On the cancellation mechanism of radiation from the Unruh detector

AU - Iso, Satoshi

AU - Yamamoto, Kazuhiro

AU - Zhang, Sen

PY - 2013/6

Y1 - 2013/6

N2 - A uniformly accelerated detector (Unruh detector) in a Minkowski vacuum is excited as if it is exposed to a thermal bath with a temperature proportional to its acceleration. In the inertial frame, since both the excitation and de-excitation of the detector are accompanied by emission of radiation into the Minkowski vacuum, one may suspect that the Unruh detector emits radiation like Larmor radiation from an accelerated charged particle. However, it is known that the radiation is miraculously canceled out by a quantum interference effect. In this paper, we investigate the conditions under which the radiation cancels out.We first show that the cancellation occurs if the Green function satisfies a relation similar to the Kubo-Martin-Schwinger (KMS) condition. We then study two examples, Unruh detectors in 3+1-dimensional Minkowski spacetime and in de Sitter spacetime. In both cases, the relation holds only in a restricted region of the spacetime, but the radiation is canceled over the whole spacetime. Hence the KMS-like relation is necessary but not sufficient for the cancellation to occur.

AB - A uniformly accelerated detector (Unruh detector) in a Minkowski vacuum is excited as if it is exposed to a thermal bath with a temperature proportional to its acceleration. In the inertial frame, since both the excitation and de-excitation of the detector are accompanied by emission of radiation into the Minkowski vacuum, one may suspect that the Unruh detector emits radiation like Larmor radiation from an accelerated charged particle. However, it is known that the radiation is miraculously canceled out by a quantum interference effect. In this paper, we investigate the conditions under which the radiation cancels out.We first show that the cancellation occurs if the Green function satisfies a relation similar to the Kubo-Martin-Schwinger (KMS) condition. We then study two examples, Unruh detectors in 3+1-dimensional Minkowski spacetime and in de Sitter spacetime. In both cases, the relation holds only in a restricted region of the spacetime, but the radiation is canceled over the whole spacetime. Hence the KMS-like relation is necessary but not sufficient for the cancellation to occur.

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U2 - 10.1093/ptep/ptt040

DO - 10.1093/ptep/ptt040

M3 - Article

AN - SCOPUS:84879171502

VL - 2013

JO - Progress of Theoretical and Experimental Physics

JF - Progress of Theoretical and Experimental Physics

SN - 2050-3911

IS - 6

M1 - 063B01

ER -