Measuring spin correlations in optical lattices using superlattice potentials

TL;DR

This paper proposes two experimental techniques using superlattice potentials to measure spin correlations, including antiferromagnetic and d-wave pairing, in optical lattices with potential applications in quantum simulation.

Contribution

It introduces novel methods for probing spin correlations in optical lattices, enabling detection of AF and d-wave pairing states with large signatures in single experimental shots.

Findings

Both methods produce large signatures of AF correlations in experiments.

The techniques can detect d-wave pairing in doped Hubbard models.

Methods are effective for strongly interacting fermionic atoms.

Abstract

We suggest two experimental methods for probing both short- and long-range spin correlations of atoms in optical lattices using superlattice potentials. The first method involves an adiabatic doubling of the periodicity of the underlying lattice to probe neighboring singlet (triplet) correlations for fermions (bosons) by the occupation of the new vibrational ground state. The second method utilizes a time-dependent superlattice potential to generate spin-dependent transport by any number of prescribed lattice sites, and probes correlations by the resulting number of doubly occupied sites. For experimentally relevant parameters, we demonstrate how both methods yield large signatures of antiferromagnetic (AF) correlations of strongly repulsive fermionic atoms in a single shot of the experiment. Lastly, we show how this method may also be applied to probe d-wave pairing, a possible ground state candidate for the doped repulsive Hubbard model.