Accelerated paths and Unruh effect: finite time detector response in (anti) de Sitter spacetime and Huygen's principle

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.