Decoherence in quantum cavities: Environmental erasure of carpet-type structures

Abstract

The interaction with an environment provokes decoherence in quantum systems, which gradually suppresses their capability to display interference traits. Hence carpet-type patterns formed in quantum cavities constitute ideal systems to study the robustness of the underlying interference process against the harmful effects of decoherence. This fact is here numerically investigated by means of a simple dynamical model that captures the essential features of the phenomenon under Markovian conditions, thus leaving aside extra complications associated with a more detailed dynamical description of the system-environment interaction. More specifically, this model takes into account and reproduces the fact that decoherence effects are stronger as energy levels become more separated (in energy), which translates into a progressive collapse of the energy density matrix to its main diagonal. However, because energy dissipation is not considered, an analogous behavior is not observed in the position representation, where a proper spatial localization of the probability density does not take place, as one might expected, but a rather delocalized distribution. Furthermore, it is also shown that in this representation some off-diagonal correlations still persist, which requires the consideration of an additional spatial-type factor. This makes evident the rather complex nature of the decoherence phenomenon and hence the importance to have a good acquaintance with how it manifests in different representations with the purpose to determine and design reliable control mechanisms.I.