Ja n 20 04 Vacuum fluctuations and moving atoms / detectors : From Casimir - Polder to Unruh Effect

In this note we report on some new results [1] on corrections to the Casimir-Polder [2] retardation force due to atomic motion and present a preliminary (unpublished) critique on one recently proposed cavity QED detection scheme of Unruh effect [3]. These two well-known effects arise from the interaction between a moving atom or detector with a quantum field under some boundary conditions introduced by a conducting mirror/cavity or dielectric wall. The Casimir-Polder force is a retardation force on the atom due to the dressing of the atomic ground state by the vacuum electromagnetic field in the presence of a conducting mirror or dielectric wall. We have recently provided an improved calculation by treating the mutual influence of the atom and the (constrained) field in a self-consistent way. For an atom moving adiabatically, perpendicular to a mirror, our result finds a coherent retardation correction up to twice the stationary value. Unruh effect refers loosely to the fact that a uniformly accelerated detector feels hot. Two prior schemes have been proposed for the detection of 'Unruh radiation', based on charged particles in linear accelerators and storage rings. Here we are interested in a third scheme proposed recently by Scully et al [4] involving the injection of accelerated atoms into a microwave or optical cavity. We analyze two main factors instrumental to the purported success in this scheme, the cavity factor and the sudden switch-on factor. We conclude that the effects engendered from these factors are unrelated to the Unruh effect.