Search

We show that it is possible to still use semiclassical gravity together with quantum field theory beyond the regimes where the field state is coherent. In particular, we identify families of cat states (superposition of almost-distinguishable coherent states that have very non-classical features) for which the gravitational backreaction can be modeled by semiclassical gravity., Comment: 9 pages, 1 Appendix. RevTeX 4.2

We study the finite time response of an Unruh-DeWitt particle detector described by a qubit (two-level system) moving with uniform constant acceleration in maximally symmetric spacetimes. The $D$ dimensional massless fermionic response function in de Sitter (dS) background is found to be identical to that of a detector linearly coupled to a massless scalar field in $2D$ dimensional dS background. Furthermore, we visit the status of Huygen's principle in the Unruh radiation observed by the detector.