Collisional scattering of strongly interacting D-band Feshbach molecules in optical lattices

TL;DR

This study explores how strong interactions affect collisional scattering and lifetimes of $^{6} m Li_2$ molecules in the $D$ band of optical lattices, combining experimental measurements and theoretical modeling.

Contribution

It provides the first detailed analysis of high-band molecular scattering dynamics under strong interactions, including a two-body scattering rate model.

Findings

D-band lifetimes depend on interaction strength.

Maximum lifetime varies with lattice depth.

Scattering channels are influenced by interaction levels.

Abstract

The excited bands in optical lattices manifest an important tool for studying quantum simulation and many-body physics, making it crucial to measure high-band scattering dynamics under strong interactions. This work investigates both experimentally and theoretically the collisional scattering of $^{6}\rm Li_2$ molecular Bose-Einstein condensate in the $D$ band of a one-dimensional optical lattice, with interaction strength directly tunable via magnetic Feshbach resonance. We find a clear dependence of the $D$-band lifetimes on the interaction strength within the strongly interacting regime, which arises from the fact that the scattering cross-section is proportional to the square of the scattering length. The maximum lifetime versus lattice depth is measured to reveal the effects of interactions. We also investigate the scattering channels of $D$-band molecules under different interaction levels and develop a reliable two-body scattering rate equation. This work provides insight into the interplay between interaction and the collisional scattering of high-band bosons in optical lattices, paving the way for research into strong correlation effects in high-band lattice systems.