5 research outputs found
Dynamical Casimir Effect and Quantum Cosmology
We apply the background field method and the effective action formalism to
describe the four-dimensional dynamical Casimir effect. Our picture corresponds
to the consideration of quantum cosmology for an expanding FRW universe (the
boundary conditions act as a moving mirror) filled by a quantum massless GUT
which is conformally invariant. We consider cases in which the static Casimir
energy is repulsive and attractive. Inserting the simplest possible inertial
term, we find, in the adiabatic (and semiclassical) approximation, the
dynamical evolution of the scale factor and the dynamical Casimir stress
analytically and numerically (for SU(2) super Yang-Mills theory). Alternative
kinetic energy terms are explored in the Appendix.Comment: 14 pages, REVTeX 4, 6 eps figure
Casimir energy and a cosmological bounce
We review different computation methods for the renormalised energy momentum
tensor of a quantised scalar field in an Einstein Static Universe. For the
extensively studied conformally coupled case we check their equivalence; for
different couplings we discuss violation of different energy conditions. In
particular, there is a family of masses and couplings which violate the weak
and strong energy conditions but do not lead to spacelike propagation. Amongst
these cases is that of a minimally coupled massless scalar field with no
potential. We also point out a particular coupling for which a massless scalar
field has vanishing renormalised energy momentum tensor. We discuss the
backreaction problem and in particular the possibility that this Casimir energy
could both source a short inflationary epoch and avoid the big bang singularity
through a bounce.Comment: 13 pages, LaTeX, 8 figure