2D Superexchange mediated magnetization dynamics in an optical lattice

TL;DR

This study investigates non-equilibrium magnetization dynamics in a 2D optical lattice, revealing superexchange-driven relaxation processes and demonstrating control over tunneling and superexchange interactions in a quantum many-body system.

Contribution

It introduces a method to separately control tunneling and superexchange in a 2D optical lattice, enabling detailed study of their roles in magnetization dynamics.

Findings

Relaxation dynamics show two distinct rates linked to superexchange and tunneling.

Superexchange-driven dynamics are observable over a wide range of magnetic couplings.

Measured timescales align with theoretical estimates despite complex many-body effects.

Abstract

The competition of magnetic exchange interactions and tunneling underlies many complex quantum phenomena observed in real materials. We study non-equilibrium magnetization dynamics in an extended 2D system by loading effective spin-1/2 bosons into a spin-dependent optical lattice, and we use the lattice to separately control the resonance conditions for tunneling and superexchange. After preparing a non-equilibrium anti-ferromagnetically ordered state, we observe relaxation dynamics governed by two well-separated rates, which scale with the underlying Hamiltonian parameters associated with superexchange and tunneling. Remarkably, with tunneling off-resonantly suppressed, we are able to observe superexchange dominated dynamics over two orders of magnitude in magnetic coupling strength, despite the presence of vacancies. In this regime, the measured timescales are in agreement with simple theoretical estimates, but the detailed dynamics of this 2D, strongly correlated, and far-from-equilibrium quantum system remain out of reach of current computational techniques.