Fermions in 3D Optical Lattices: Cooling Protocol to Obtain Antiferromagnetism

Thereza Paiva, Yen Lee Loh, Mohit Randeria, Richard T. Scalettar, and Nandini Trivedi

Phys. Rev. Lett. 107, 086401 – Published 17 August 2011

Abstract

A major challenge in realizing antiferromagnetic and superfluid phases in optical lattices is the ability to cool fermions. We determine the equation of state for the 3D repulsive Fermi-Hubbard model as a function of the chemical potential, temperature, and repulsion using unbiased determinantal quantum Monte Carlo methods, and we then use the local density approximation to model a harmonic trap. We show that increasing repulsion leads to cooling but only in a trap, due to the redistribution of entropy from the center to the metallic wings. Thus, even when the average entropy per particle is larger than that required for antiferromagnetism in the homogeneous system, the trap enables the formation of an antiferromagnetic Mott phase.

Received 12 May 2011

DOI:https://doi.org/10.1103/PhysRevLett.107.086401

Authors & Affiliations

Thereza Paiva¹, Yen Lee Loh², Mohit Randeria², Richard T. Scalettar³, and Nandini Trivedi²

¹Instituto de Fisica, Universidade Federal do Rio de Janeiro Cx.P. 68.528, 21941-972 Rio de Janeiro RJ, Brazil
²Department of Physics, The Ohio State University, Columbus, Ohio 43210, USA
³Department of Physics, University of California, Davis, California 95616, USA