Fermionic Casimir densities for a uniformly accelerating mirror in the Fulling-Rindler vacuum

TL;DR

This paper analyzes the fermionic vacuum characteristics near a uniformly accelerating boundary in Rindler spacetime, revealing how boundary conditions influence vacuum expectation values and energy densities.

Contribution

It provides a detailed calculation of fermionic vacuum expectation values in accelerated boundary scenarios, highlighting boundary and mass effects in Rindler spacetime.

Findings

Boundary-free contributions dominate near the Rindler horizon.

Boundary-induced effects are significant near the boundary, with signs depending on the region.

Massless fields show distinct behavior, with vanishing fermion condensate in higher dimensions.

Abstract

We investigate the local characteristics of the Fulling-Rindler vacuum for a massive Dirac field induced by a planar boundary moving with constant proper acceleration in $(D+1)$-dimensional flat spacetime. On the boundary, the field operator obeys the bag boundary condition. The boundary divides the right Rindler wedge into two separate regions, called RL and RR regions. In both these regions, the fermion condensate and the vacuum expectation value (VEV) of the energy-momentum tensor are decomposed into two contributions. The first one presents the VEVs in the Fulling-Rindler vacuum when the boundary is absent and the second one is the boundary-induced contribution. For points away from the boundary, the renormalization is reduced to the one for the boundary-free geometry. The total VEVs are dominated by the boundary-free parts near the Rindler horizon and by the boundary-induced parts in the region near the boundary. For a massive field the boundary-free contributions in the fermion condensate and the vacuum energy density and effective pressures are negative everywhere. The boundary-induced contributions in the fermion condensate and the energy density are positive in the RL region and negative in the RR region. For a massless field the fermion condensate vanishes in spatial dimensions $D\geq 2$, while the VEV of the energy-momentum tensor is different from zero. This behavior contrasts with that of the VEVs in the Minkowski vacuum for the geometry of a boundary at rest relative to an inertial observer. In the latter case, the fermion condensate for a massless field is nonzero, while the VEV of the energy-momentum tensor becomes zero. The obtained results are used to investigate the VEV of the fermionic energy-momentum tensor in weak gravitational fields and background geometries that are conformally related to Rindler spacetime.