Phases in optical lattices vs. Coulomb frustrated HTc cuprates

TL;DR

This paper compares the phase diagrams of fermionic atoms in optical lattices and electrons in high-temperature cuprates, highlighting differences caused by Coulomb frustration and proposing experimental detection methods.

Contribution

It introduces a comparative analysis of stripe and antiferromagnetic phases in optical lattices and cuprates, emphasizing the role of Coulomb frustration and phase separation.

Findings

Different phase behaviors in optical lattices and cuprates due to Coulomb effects.

Distinct Mott plateau structures and density discontinuities in confined systems.

Proposed experimental signatures for detecting phases via time-of-flight measurements.

Abstract

Fermionic atoms in 2D optical lattices and electrons in HTc cuprates may both be described by the Hubbard model. However, if Coulomb frustration is responsible for the striped phases in 2D cuprates the phase diagrams will differ markedly. Two representative scenarios are described by a simple stripe model without phase separation and a mean field model with phase separation in the absence of Coulomb frustration. When Coulomb frustrated both models display antiferromagnetism (AF) and stripe phases with d-wave superfluidity, whereas neutral atoms in optical lattices will only do so in the stripe model. Radii and densities of the various phases in harmonically confined optical lattices are calculated for the two models and have very different Mott plateaus and density discontinuities. We discuss observation of antiferromagnetic, stripe and superfluid phases in density and momentum distributions and correlations from time-of-flight experiments.