Ground State and Excitations of Disordered Boson Systems

TL;DR

This paper develops a Gaussian theoretical framework, equivalent to Bogoliubov approximation, to analyze the ground state and excitations of disordered boson systems, revealing how disorder can destroy off-diagonal long-range order and affect excitation properties.

Contribution

It introduces a Gaussian approach to study disordered bosons, providing insights into the destruction of off-diagonal long-range order due to disorder.

Findings

Disorder can destroy off-diagonal long-range order in boson systems.

Density of states of excitations is characterized.

Localization properties of elementary excitations are discussed.

Abstract

After an introduction to the dirty bosons problem, we present a gaussian theory for the ground state and excitations. This approach is physically equivalent to the Bogoliubov approximation. We find that ODLRO can be destroyed with sufficient disorder. The density of states and localization of the elementary excitations are discussed. (To appear in JLTP Proceedings of the Conference on Condensed Bose Systems at the University of Minnesota, 1993.)