Backreaction and the Unruh effect: New insights from exact solutions of uniformly accelerated detectors

Journal Article · Sat Sep 15 00:00:00 EDT 2007 · Physical Review. D, Particles Fields

DOI:https://doi.org/10.1103/PHYSREVD.76.064008· OSTI ID:21027775

Lin, S -Y; Hu, B L ^[1]

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1. Physics Division, National Center for Theoretical Sciences, P.O. Box 2-131, Hsinchu 30013, Taiwan (China)

Using nonperturbative results obtained recently for a uniformly accelerated Unruh-DeWitt detector, we discover new features in the dynamical evolution of the detector's internal degree of freedom, and identified the Unruh effect derived originally from time-dependent perturbation theory as operative in the ultraweak coupling and ultrahigh acceleration limits. The mutual interaction between the detector and the field engenders entanglement between them, and tracing out the field leads to a mixed state of the detector even for a detector at rest in Minkowski vacuum. Our findings based on this exact solution show clearly the differences from the ordinary result where the quantum field's backreaction is ignored in that the detector no longer behaves like a perfect thermometer. From a calculation of the evolution of the reduced density matrix of the detector, we find that the transition probability from the initial ground state over an infinitely long duration of interaction derived from time-dependent perturbation theory is existent in the exact solution only in transient under special limiting conditions corresponding to the Markovian regime. Furthermore, the detector at late times never sees an exact Boltzmann distribution over the energy eigenstates of the free detector, thus in the non-Markovian regime covering a wider range of parameters the Unruh temperature cannot be identified inside the detector.

• OSTI ID: 21027775
• Journal Information: Physical Review. D, Particles Fields, Vol. 76, Issue 6; Other Information: DOI: 10.1103/PhysRevD.76.064008; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ACCELERATION
COUPLING
DEGREES OF FREEDOM
DENSITY MATRIX
DISTRIBUTION
EIGENSTATES
EXACT SOLUTIONS
GROUND STATES
MARKOV PROCESS
MINKOWSKI SPACE
MIXED STATE
PERTURBATION THEORY
PROBABILITY
QUANTUM ENTANGLEMENT
QUANTUM FIELD THEORY
TIME DEPENDENCE
TRANSIENTS