Density Operator Description of Atomic Ordered Spatial Modes in Cavity QED

TL;DR

This paper introduces a density operator model and quantum Monte-Carlo simulation to analyze atomic spatial modes in cavity QED, revealing the formation and dynamics of ordered modes with dissipation effects.

Contribution

It develops a mixed state density operator approach and a new decomposition method to describe atomic spatial modes and cavity field statistics beyond pure states.

Findings

Density operator model accurately describes the system.

Ordered atomic spatial modes form in the cavity.

Dynamical probabilities of modes are analyzed.

Abstract

We present a quantum Monte-Carlo simulation for a pumped atom in a strong coupling cavity with dissipation, where two ordered spatial modes are formed for the atomic probability density, with the peaks distributed either only in the odd sites or only in the even ones of the lattice formed by the cavity field. A mixed state density operator model, which describes the coupling between different atomic spatial modes and the corresponding cavity field components, is proposed, which goes beyond the pure state interpretation. We develop a new decomposition treatment to derive the atomic spatial modes as well as the cavity field statistics from the simulation results for the steady state. With this treatment, we also investigate the dynamical process for the probabilities of the atomic spatial modes in the adiabatic limit. According to the analysis of the fitting error between the simulation results and the density operator model, the latter is a good description for the system.