Sudden death of particle-pair Bloch oscillation and unidirectional propagation in a one-dimensional driven optical lattice

TL;DR

This paper investigates the dynamics of bound pairs in a driven optical lattice, revealing phenomena like Bloch-Zener oscillations and sudden death of oscillations, which help characterize bound state phases.

Contribution

It demonstrates the existence of bound pairs in the extended Hubbard model and describes their distinct dynamical behaviors under external driving.

Findings

Bound pairs form in the absence of external fields.

Perfect bands exhibit Bloch-Zener oscillations.

Imperfect bands show sudden death of oscillations.

Abstract

We study the dynamics of bound pairs in the extended Hubbard model driven by a linear external field. It is shown that two interacting bosons or singlet fermions with nonzero on-site and nearest-neighbor interaction strengths can always form bound pairs in the absence of an external field. There are two bands of bound pairs, one of which may have incomplete wave vectors when it has an overlap with the scattering band, referred to as an imperfect band. In the presence of the external field, the dynamics of the bound pair in the perfect band exhibits distinct Bloch-Zener oscillation (BZO), while in the imperfect band the oscillation presents a sudden death. The pair becomes uncorrelated after the sudden death and the BZO never comes back. Such dynamical behaviors are robust even for the weak-coupling regime and thus can be used to characterize the phase diagram of the bound states.