Functional approach to quantum friction: Effective action and dissipative force

M. BELEN FARIAS, C. D. FOSCO, F. C. LOMBARDO, F. D. MAZZITELLI, G. TURIACI, A. RUBIO LOPEZ

PHYSICAL REVIEW D - PARTICLE AND FILDS

American Institute of Physics

Lugar: New York; Año: 2015 vol. 91 p. 1050201 - 10502010

0556-2821

We study the Casimir friction due to the relative, uniform, lateral motion of two parallel semitransparent mirrors coupled to a vacuum real scalar field ␣. We follow a functional approach, whereby nonlocal terms in the action for ␣, concentrated on the mirrors? loci, appear after functional integration of the microscopic degrees of freedom. This action for ␣, which incorporates the relevant properties of the mirrors, is then used as the starting point for two complementary evaluations: Firstly, we calculate the in-out effective action for the system, which develops an imaginary part, hence a nonvanishing probability for the decay (because of friction) of the initial vacuum state. Secondly, we evaluate another observable: the vacuum expectation value of the frictional force, using the in-in or closed time path formalism. Explicit results are presented for zero-width mirrors and half-spaces, in a model where the microscopic degrees of freedom at the mirrors are a set of identical quantum harmonic oscillators, linearly coupled to phi