Controlling Correlated Tunneling and Superexchange Interactions with AC-Driven Optical Lattices

TL;DR

This paper demonstrates how AC-driven optical lattices can coherently control single-particle and correlated two-particle tunneling, as well as superexchange interactions, enabling precise simulation of complex spin models in ultracold gases.

Contribution

It introduces a method to extend dynamical control to strongly interacting particles and realizes arbitrary XXZ spin models with full control over couplings.

Findings

Coherent control of single and two-particle hopping processes.

Extension of control to superexchange spin interactions with magnetic-field gradients.

Realization of arbitrary XXZ spin models in ultracold quantum gases.

Abstract

The dynamical control of tunneling processes of single particles plays a major role in science ranging from Shapiro steps in Josephson junctions to the control of chemical reactions via light in molecules. Here we show how such control can be extended to the regime of strongly interacting particles. Through a weak modulation of a biased tunnel contact, we have been able to coherently control single particle and correlated two-particle hopping processes. We have furthermore been able to extend this control to superexchange spin interactions in the presence of a magnetic-field gradient. We show how such photon assisted superexchange processes constitute a novel approach to realize arbitrary XXZ spin models in ultracold quantum gases, where transverse and Ising type spin couplings can be fully controlled in magnitude and sign.