Critical entropies for magnetic ordering in bosonic mixtures on a lattice

TL;DR

This study uses Monte Carlo simulations to determine the critical entropies and temperatures for magnetic ordering in ultracold bosonic mixtures on optical lattices, highlighting experimental challenges due to low entropy thresholds.

Contribution

It provides the first quantitative estimates of critical entropies and hold times necessary for observing magnetic phases in bosonic lattice systems.

Findings

Critical entropy per particle is approximately 0.5kB.

Magnetic order disappears at specific critical temperatures.

Experimental observation requires precise control of heating and entropy.

Abstract

We perform a numeric study (worm algorithm Monte Carlo simulations) of ultracold two-component bosons in two- and three-dimensional optical lattices. At strong enough interactions and low enough temperatures the system features magnetic ordering. We compute critical temperatures and entropies for the disappearance of the Ising antiferromagnetic and the xy-ferromagnetic order and find that the largest possible entropies per particle are ~0.5kB. We also estimate (optimistically) the experimental hold times required to reach equilibrium magnetic states to be on a scale of seconds. Low critical entropies and long hold times render the experimental observations of magnetic phases challenging and call for increased control over heating sources.