# Collective excitations and tunneling dynamics in long bosonic Josephson junctions

## TL;DR

This paper studies the low-energy excitations and tunneling dynamics of long bosonic Josephson junctions using advanced theoretical models, revealing complex oscillation behaviors beyond standard equations.

## Contribution

It introduces a comprehensive analysis combining 2D Gross-Pitaevskii and Bogoliubov-de Gennes formalisms, along with a 1D hydrodynamic model, to better understand coupled Bose-Einstein condensates.

## Key findings

- Multiple-frequency oscillations of atomic populations are explained by low-energy excitations.
- The developed models accurately reproduce the excitation spectrum and population dynamics.
- Generalization of the standard Josephson equations to include complex excitation effects.

## Abstract

We investigate the low-energy dynamics of two coupled anisotropic Bose-Einstein condensates forming a long Josephson junction. The theoretical study is performed in the framework of the two-dimensional Gross-Pitaevskii equation and the Bogoliubov-de Gennes formalism. We analyze the excitation spectrum of the coupled Bose condensates and show how low-energy excitations of the condensates lead to multiple-frequency oscillations of the atomic populations in the two wells. This analysis generalizes the standard bosnic Josephson euqation approach. We also develop a one-dimensional hydrodynamic model of the coupled condensates, that is capable to reproduce the excitation spectrum and population dynamics of the system.