Method of canonical transformations in the theory of quantum gases interacting with radiation

TL;DR

This paper introduces a modified canonical transformation method to analyze quantum gases interacting with radiation, enabling the study of photon effects on atomic spectra and the concept of dressed atoms as quasiparticles.

Contribution

It develops a novel approach based on modified canonical transformations to investigate photon interactions in quantum gases, extending previous methods used for electron-phonon systems.

Findings

Demonstrates the influence of photons on atomic spectral characteristics.

Derives expressions for the energy of dressed atoms as quasiparticles.

Discusses the concept of effective mass for these quasiparticles.

Abstract

An approach to the theoretical study of effects and phenomena in quantum gases interacting with radiation is proposed. The approach is based on a modification of the canonical transformation method, which was once used to diagonalize Hamiltonians describing the interaction of electrons with phonons in a solid. The capabilities of the method are demonstrated by studying the influence of photons on the spectral characteristics of atoms of quantum gases interacting with radiation. Within the framework of the developed approach, the effect of "dressing" atoms of quantum gases by a cloud of virtual photons is investigated and expressions for the energy characteristics of such dressed atoms - quasiparticles are obtained. The problem of defining the concept of the effective mass of such quasiparticles is discussed.