Non-equilibrium quantum magnetism in a dipolar lattice gas

TL;DR

This paper reports the first experimental realization of quantum magnetism using a degenerate dipolar gas in an optical lattice, enabling direct study of spin interactions without super-exchange, and explores high-spin quantum magnetism.

Contribution

It demonstrates a novel approach to quantum magnetism with dipolar gases, realizing a lattice model similar to the t-J model with non-local dipole-dipole interactions.

Findings

Realization of a chromium dipolar gas in a 3D lattice mimicking the t-J model.

Observation of non-equilibrium spinor dynamics due to dipole-dipole interactions.

Complex spin dynamics in high-spin systems with doubly-occupied sites.

Abstract

Research on quantum magnetism with ultra-cold gases in optical lattices is expected to open fascinating perspectives for the understanding of fundamental problems in condensed-matter physics. Here we report on the first realization of quantum magnetism using a degenerate dipolar gas in an optical lattice. In contrast to their non-dipolar counterparts, dipolar lattice gases allow for inter-site spin-spin interactions without relying on super-exchange energies, which constitutes a great advantage for the study of spin lattice models. In this paper we show that a chromium gas in a 3D lattice realizes a lattice model resembling the celebrated t-J model, which is characterized by a non-equilibrium spinor dynamics resulting from inter-site Heisenberg-like spin-spin interactions provided by non-local dipole-dipole interactions. Moreover, due to its large spin, chromium lattice gases constitute an excellent environment for the study of quantum magnetism of high-spin systems, as illustrated by the complex spin dynamics observed for doubly-occupied sites.