Exact Description of Decoherence in Optical Cavities

TL;DR

This paper derives an exact description of decoherence in optical cavities, showing that the environment's influence can be fully characterized by a few measurable functions, simplifying the experimental mapping of quantum state evolution.

Contribution

It provides an exact reduced dynamics model for optical cavities, identifying key measurable functions that fully describe the decoherence process at various temperatures.

Findings

Decoherence dynamics are encapsulated in two or three real functions of time.

Measuring these functions suffices to map the evolution of various quantum states.

The model applies at both zero and finite temperatures.

Abstract

The exact reduced dynamics for the independent oscillator model in the RWA approximation at zero and finite temperatures is derived. It is shown that the information about the interaction and the environment is encapsulated into three time dependent coefficients of the master equation, one of which vanishes in the zero temperature case. In currently used optical cavities all the information about the field dynamics is contained into {\it two} (or three) experimentally accesible and physically meaningful real functions of time. From the phenomenological point of view it suffices then to carefully measure two ({\it three}) adequate observables in order to map the evolution of any initial condition, as shown with several examples: (generalized) coherent states, Fock states, Schr\"odinger cat states, and squeezed states.