2013/08/01 by Stefano Bellucci, S. Bellucci, A. A. Saharian
Mathematics · Physics and Astronomy · #Casimir effect #Classical mechanics #Cosmology #Cosmology and Gravitation Theories #Curvature #Dark energy #Electromagnetic field #Geometry #Mathematical physics #Mathematics #Metric expansion of space #Minkowski space #Noncommutative and Quantum Gravity Theories #Physics #Quantum #Quantum Electrodynamics and Casimir Effect #Quantum electrodynamics #Quantum field theory in curved spacetime #Quantum gravity #Quantum mechanics #Scale factor (cosmology) #Spacetime #Tensor (intrinsic definition) #Vacuum energy #Vacuum state #astro-ph.CO #gr-qc #hep-th
paper · pdf · doi:10.1103/physrevd.88.064034
published as Phys. Rev. D 88 (2013) 064034 · 25 pages, 4 figures
arxiv created 2013/08/01 · openalex publication_date 2013/09/17 · arxiv updated 2013/11/15 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We evaluate the two-point functions of the electromagnetic field in (D+1)-dimensional spatially flat Friedmann--Robertson--Walker universes with a power-law scale factor, assuming that the field is prepared in the Bunch--Davies vacuum state. The range of powers is specified in which the two-point functions are infrared convergent and the Bunch--Davies vacuum for the electromagnetic field is a physically realizable state. The two-point functions are applied for the investigation of the vacuum expectation values of the field squared and the energy-momentum tensor, induced by a single and two parallel conducting plates. Unlike to the case of conducting plates in the Minkowski bulk, in the problem under consideration, the stresses along the directions parallel to the plates are not equal to the energy density. We show that, in addition to the diagonal components, the vacuum energy-momentum tensor has a nonzero off-diagonal component which describes energy flux along the direction normal to the plates. For a single plate, this flux is directed from the plate. The Casimir forces are investigated in the geometry of two plates. At separations between the plates smaller than the curvature radius of the background spacetime, to the leading order, we recover the corresponding result in the Minkowski spacetime, and in this case the forces are attractive. At larger separations, the influence of the curvature on the Casimir forces is essential with different asymptotic behavior for decelerated and accelerated expansions. In particular, for the latter case, there is a range of powers of the expansion law in which the forces become repulsive at large separations between the plates.