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Loss of coherence in multidimensional minisuperspaces

Journal Article · · Physical Review, D (Particles Fields); (USA)
; ;  [1]
  1. Instituto de Astronomia y Fisica del Espacio, Casilla de Correo 67, Sucursal 28, 1428 Buenos Aires, Argentina (AR) Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellon I, 1428 Buenos Aires, Argentina
In the semiclassical limit of quantum gravity, solutions to the Wheeler-DeWitt equation involve several WKB components. In order to reach the adequate classical limit these contributions should not interfere. We show here that this is in general the case. We work with a general minisuperspace model with perturbations and we construct the reduced density matrix {tilde {rho}}({ital g}{sub {ital A}},{ital g}{sub {ital A}}{sup {prime}}) by tracing out all the nonrelevant modes of the environment. It turns out that not only are the off-diagonal terms of {tilde {rho}}({ital g}{sub {ital A}},{ital g}{sub {ital A}}{sup {prime}}) strongly suppressed but the quantum contributions to {tilde {rho}}({ital g}{sub {ital A}},{ital g}{sub {ital A}}) due to interference between different semiclassical solutions also vanish. As an example we discuss the particular case of the Kantowski-Sachs cosmological model.
OSTI ID:
5864896
Journal Information:
Physical Review, D (Particles Fields); (USA), Journal Name: Physical Review, D (Particles Fields); (USA) Vol. 43:6; ISSN PRVDA; ISSN 0556-2821
Country of Publication:
United States
Language:
English