Tunable Single-Ion Anisotropy in Spin-1 Models Realized with Ultracold Atoms

TL;DR

This paper demonstrates how ultracold atoms in optical lattices can be used to realize and control tunable single-ion anisotropy in spin-1 models, enabling the study of magnetic phenomena in low-dimensional systems.

Contribution

It introduces a method to implement and tune single-ion anisotropy in ultracold atom systems, supported by experimental observations, numerical simulations, and analytical modeling.

Findings

Resonant effect in spin anisotropy as a function of lattice depth.

Agreement between experimental results, numerical simulations, and analytical models.

Potential to explore magnetic phenomena in low-dimensional quantum systems.

Abstract

Mott insulator plateaus in optical lattices are a versatile platform to study spin physics. Using sites occupied by two bosons with an internal degree of freedom, we realize a uniaxial single-ion anisotropy term proportional to $(S^z)^2$, which plays an important role in stabilizing magnetism for low-dimensional magnetic materials. Here we explore non-equilibrium spin dynamics and observe a resonant effect in the spin anisotropy as a function of lattice depth when exchange coupling and on-site anisotropy are similar. Our results are supported by many-body numerical simulations and are captured by the analytical solution of a two-site model.