Quantum dynamics of repulsively bound atom pairs in the Bose-Hubbard model

TL;DR

This paper explores the quantum behavior of repulsively bound atom pairs in an optical lattice, revealing their stability and self-localization under strong interactions through analytical and numerical methods.

Contribution

It provides a combined analytical and numerical analysis of atom pair dynamics in the Bose-Hubbard model, highlighting the stability and self-localization phenomena in the strongly repulsive regime.

Findings

Atom pairs are dynamically stable under strong repulsion.

Strong on-site interactions suppress atom pair dissociation.

Self-localization of atom pairs occurs in the strongly repulsive limit.

Abstract

We investigate the quantum dynamics of repulsively bound atom pairs in an optical lattice described by the periodic Bose-Hubbard model both analytically and numerically. In the strongly repulsive limit, we analytically study the dynamical problem by the perturbation method with the hopping terms treated as a perturbation. For a finite-size system, we numerically solve the dynamic problem in the whole regime of interaction by the exact diagonalization method. Our results show that the initially prepared atom pairs are dynamically stable and the dissociation of atom pairs is greatly suppressed when the strength of the on-site interaction is much greater than the tunneling amplitude, i.e., the strongly repulsive interaction induces a self-localization phenomenon of the atom pairs.