Observable Unruh Effect and Unmasked Unruh Radiation
The Unruh effect, thereby an ideally accelerated quantum detector is predicted to absorb thermalized virtual photons and re-emit real photons, is significantly extended for laboratory accessible configurations. Using modern influence functional techniques, we obtain explicit expressions describing the excitation and relaxation of the quantum levels of an Unruh detector as a general noninertial open quantum system. Remarkably, for controllable periodical motions, an exact master equation is found for the Unruh detector within the prevailing framework of quantum optics with a well-defined Unruh temperature for given acceleration ($α$), acceleration frequency ($ω_α$), and transition frequency ($ω_0$) of the detector. We further show that the measurable Unruh temperatures and corresponding transition rates are comparable or higher than their values for the ideally accelerated cases if $cω_0$ and $cω_α$ have similar orders of magnitude as $α$. This allows us to select the transition rates of the detector to unmask Unruh radiation against Larmor radiation which has been a major competing noise. Our work suggests experiments with such settings may directly confirm the Unruh effect within the current technology, based on which a laboratory test of black hole thermodynamics will become possible.