Interaction-Induced Adiabatic Cooling for Antiferromagnetism in Optical Lattices

TL;DR

This paper investigates how adiabatic manipulation of interactions in cold-fermion optical lattices can facilitate reaching antiferromagnetic phases, providing quantitative isentropic curves and analyzing effectiveness in different dimensions.

Contribution

It offers the first detailed quantitative analysis of adiabatic cooling strategies for antiferromagnetism in optical lattices using advanced simulation methods.

Findings

Adiabatic cooling in 2D is not very effective.

In 3D, adiabatic cooling can reach antiferromagnetic order.

Cooling efficiency is lower than initial theoretical estimates.

Abstract

In the experimental context of cold-fermion optical lattices, we discuss the possibilities to approach the pseudogap or ordered phases by manipulating the scattering length or the strength of the laser-induced lattice potential. Using the Two-Particle Self-Consistent Approach as well as Quantum Monte Carlo simulations, we provide isentropic curves for the two- and three-dimensional Hubbard models at half-filling. These quantitative results are important for practical attempts to reach the ordered antiferromagnetic phase in experiments on optical lattices of two-component fermions. We find that adiabatically turning on the interaction in two dimensions to cool the system is not very effective. In three dimensions, adiabatic cooling to the antiferromagnetic phase can be achieved in such a manner although the cooling efficiency is not as high as initially suggested by Dynamical Mean-Field Theory. Adiabatic cooling by turning off the repulsion beginning at strong coupling is possible in certain cases.