Linear response theory for a pair of coupled one-dimensional condensates of interacting atoms

TL;DR

This paper applies the quantum sine-Gordon model to analyze the low-energy excitations of coupled one-dimensional atomic condensates, proposing experimental methods to observe soliton and breather excitations through modulation techniques.

Contribution

It introduces a theoretical framework using the sine-Gordon model to describe coupled condensates and predicts observable excitation spectra in experiments.

Findings

Identification of soliton and breather excitations in the spectrum.

Proposal of experimental modulation techniques to observe these excitations.

Calculation of structure factors for different perturbations.

Abstract

We use quantum sine-Gordon model to describe the low energy dynamics of a pair of coupled one-dimensional condensates of interacting atoms. We show that the nontrivial excitation spectrum of the quantum sine-Gordon model, which includes soliton and breather excitations, can be observed in experiments with time-dependent modulation of the tunneling amplitude, potential difference between condensates, or phase of tunneling amplitude. We use the form-factor approach to compute structure factors corresponding to all three types of perturbations.