Dispersion relations and self-localization of quasiparticles in coupled elongated Bose-Einstein condensates

TL;DR

This paper investigates the spectrum and dispersion of quasiparticles in coupled elongated Bose-Einstein condensates, revealing anomalous modes with self-localization and degeneracy through analytical and numerical methods.

Contribution

It introduces an analytically solvable model for coupled elongated BECs and compares it with numerical simulations to identify novel self-localized Bogoliubov modes.

Findings

Existence of anomalous Bogoliubov modes with degeneracy

Self-localization of certain quasiparticle modes

Reasonable agreement between analytical and numerical models

Abstract

We present a detailed study of the spectrum and dispersion of Bogoliubov quasiparticles in two coupled elongated Bose-Einstein condensates. We develop an analytically solvable model that approximates two infinite homogeneous condensates and compare its predictions to a numerical simulation of a realistic trapped system. While the comparisons show a reasonable agreement between the two models, they also manifest the existence of several anomalous Bogoliubov modes in the spectrum. These modes show degeneracy in both energy and momentum together with self-localization in the coordinate space.