Quantum dynamics of attractive versus repulsive bosonic Josephson junctions: Bose-Hubbard and full-Hamiltonian results

TL;DR

This paper compares the quantum dynamics of attractive and repulsive bosonic Josephson junctions using both the Bose-Hubbard model and exact many-body Hamiltonian calculations, revealing symmetry differences.

Contribution

It demonstrates that the Bose-Hubbard model predicts a symmetry between attractive and repulsive interactions, while the full Hamiltonian shows their dynamics differ, highlighting limitations of simplified models.

Findings

Bose-Hubbard model shows symmetry in dynamics for attractive and repulsive interactions.

Full many-body Hamiltonian reveals differences in dynamics between attractive and repulsive cases.

Symmetry in simplified models does not hold in exact many-body calculations.

Abstract

The quantum dynamics of one-dimensional bosonic Josephson junctions with attractive and repulsive interparticle interactions is studied using the Bose-Hubbard model and by numerically-exact computations of the full many-body Hamiltonian. A symmetry present in the Bose-Hubbard Hamiltonian dictates an equivalence between the evolution in time of attractive and repulsive Josephson junctions with attractive and repulsive interactions of equal magnitude. The full many-body Hamiltonian does not possess this symmetry and consequently the dynamics of the attractive and repulsive junctions are different.