6533b853fe1ef96bd12ad7de

RESEARCH PRODUCT

The limits of the rotating wave approximation in electromagnetic field propagation in a cavity

I. DolceF. PersicoRoberto Passante

subject

Condensed Matter::Quantum GasesElectromagnetic fieldPhysicsQuantum PhysicsField (physics)FOS: Physical sciencesGeneral Physics and AstronomyOptical fieldCausalityCavity quantum electrodynamicRotating wave approximation.Quantum electrodynamicsQuantum mechanicsExcited stateAtomPhysics::Atomic and Molecular ClustersRotating wave approximationPhysics::Atomic PhysicsQuantum Physics (quant-ph)Ground stateExcitation

description

We consider three two-level atoms inside a one-dimensional cavity, interacting with the electromagnetic field in the rotating wave approximation (RWA), commonly used in the atom-radiation interaction. One of the three atoms is initially excited, and the other two are in their ground state. We numerically calculate the propagation of the field spontaneously emitted by the excited atom and scattered by the second atom, as well as the excitation probability of the second and third atom. The results obtained are analyzed from the point of view of relativistic causality in the atom-field interaction. We show that, when the RWA is used, relativistic causality is obtained only if the integrations over the field frequencies are extended to $-\infty$; on the contrary, noncausal tails remain even if the number of field modes is increased. This clearly shows the limit of the RWA in dealing with subtle problems such as relativistic causality in the atom-field interaction.

https://doi.org/10.1016/j.physleta.2006.02.018