A vector type of Unruh-DeWitt–like detector

Abstract

We study a type of an Unruh-DeWitt–like detector based on a vector rather than a scalar field. This detector has two energy states and produces Larmor radiation when there is no energy gap between them. This setup indicates that Larmor radiation and Unruh radiation are two counterparts of the same phenomenon. Larmor radiation is observed in the inertial frame, while Unruh radiation is observed in an accelerated frame. The accelerated observer sees that his detector absorbed a particle inside its own accelerated horizon, while the Larmor radiation is the companion particle which leaves the accelerated observer's horizon. Since the detection is based on the electromagnetic field, this type of detector is much closer to the real world than a standard Unruh-DeWitt detector which is coupled to a scalar field.