Superexchange mediated magnetization dynamics in a 2D checkerboard optical lattice

Published

May 1, 2015

Author(s)

Elizabeth A. Goldschmidt, Roger C. Brown, Silvio B. Koller, Michael S. Foss-Feig, James V. Porto, Robert Wyllie

Abstract

The interplay of spin and motion underlies some of the most intriguing and poorly understood behaviors in many-body quantum systems. A well known example is the onset of superconductivity in cuprate compounds when mobile holes are introduced into an otherwise insulating 2D quantum magnet; understanding this theoretically is particularly challenging because the dimensionality is low enough to support strong quantum correlations, but high enough to prohibit numerical solution. Ultracold atoms in optical lattices realize tunable, idealized models of such behavior, and are expected to yield insights into the relevant equilibrium and non-equilibrium physics. Here, we study the magnetization dynamics of effective spin-1/2 bosons in a 2D optical lattice following a global quench from an initially antiferromagnetic state. The dynamics we observe is governed by a checkerboard $t$-$J$ model. By tuning the lattice configuration we observe and control the competition of tunneling and super-exchange mediated magnetic relaxation, accessing regimes where super-exchange dominates the dynamics. The timescales we measure are in good 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. In addition to establishing an experimental toolbox for the exploration of non-equilibrium dynamics in t-J models, the techniques we demonstrate lay the ground work for adiabatic preparation of low entropy spin states relevant for studies of equilibrium quantum magnetism.

Citation

Nature

Pub Type

Journals

Keywords

Quantum magnetism, quantum simulation

Citation

Goldschmidt, E. , Brown, R. , Koller, S. , Foss-Feig, M. , Porto, J. and Wyllie, R. (2015), Superexchange mediated magnetization dynamics in a 2D checkerboard optical lattice, Nature (Accessed November 21, 2024)