Excitation of an inertial Unruh detector in the Minkowski vacuum: a numerical calculation using spherical modes

We consider the excitation of a finite-length inertial Unruh detector in the Minkowski vacuum with an adiabatic switch on of the interaction in the infinite past and a sudden switch off at finite times, and obtain the excitation probability via a numerical calculation using the expansion of the quantum field in spherical modes. We evaluate first the excitation probabilities for the final states of the field with one particle per mode, and then we sum over the modes. An interesting feature is that, despite of the inertial trajectory and of the vacuum state of the field, the multipole components of the excitation probability are time-dependent quantities. We make clear how the multipole sum yields the time-independent probability characteristic to an inertial trajectory. In passing, we point out that the excitation probability for a sudden switch on of the interaction in the infinite past is precisely twice as large as that for an adiabatic switch on. The procedure can be easily extended to obtain the response of the detector along radial trajectories in spherically symmetric spacetimes.Comment: 29 pages, 10 figures; submitted to Proceedings of TIM 17 Physics Conferenc

Radiation from accelerated perfect or dispersive mirrors following prescribed relativistic asymptotically inertial trajectories

We address the question of radiation emission from both perfect and dispersive mirrors following prescribed relativistic trajectories. The trajectories considered are asymptotically inertial: the mirror starts from rest and eventually reverts to motion at uniform velocity. This enables us to provide a description in terms of in and out states. We calculate exactly the Bogolubov alpha and beta coefficients for a specific form of the trajectory, and stress the analytic properties of the amplitudes and the constraints imposed by unitarity. A formalism for the description of emission of radiation from a dispersive mirror is presented.Comment: 7 figure