Green-function method in the theory of ultraslow electromagnetic waves in an ideal gas with Bose-Einstein condensates

TL;DR

This paper develops a Green-function based microscopic approach to study ultraslow electromagnetic waves in an ideal gas of hydrogenlike atoms and Bose-Einstein condensates, analyzing their propagation and damping characteristics.

Contribution

It introduces a novel Green-function formalism combined with second quantization for quantum many-particle systems with bound states, applied to electromagnetic wave slowing in BECs.

Findings

Conditions for slowing electromagnetic waves in BECs are identified.

The influence of magnetic fields on wave slowing is analyzed.

Propagation velocity and damping rates depend on microscopic system parameters.

Abstract

We propose a microscopic approach describing the interaction of an ideal gas of hydrogenlike atoms with a weak electromagnetic field. This approach is based on the Green-function formalism and an approximate formulation of the method of second quantization for quantum many-particle systems in the presence of bound states of particles. The dependencies of the propagation velocity and damping rate of electromagnetic pulses on the microscopic characteristics of the system are studied for a gas of hydrogenlike atoms. For a Bose-Einstein condensate of alkali-metal atoms we find the conditions when the electromagnetic waves of both the optical and microwave regions are slowed. In the framework of the proposed approach, the influence of an external homogeneous and static magnetic field on the slowing phenomenon is studied.