The interplay of quantum correlations and thermal decoherence is key to understanding the fundamental properties of many-body systems. Coherence is usually easily destroyed by interaction with the environment and local fluctuations inherent to thermal ensembles. Hence experimental demonstrations of many-body quantum correlations rely on cooling the system close to its ground state or pumping it into a well-defined quantum state. Here, the authors instead show how quantum correlations can arise in the opposite limit of an infinite temperature. Motivated by recent experiments with ultracold atoms in optical lattices, they study the dynamics of a hole created in a fermionic or bosonic Mott state in the atomic limit. They demonstrate that the propagating hole entangles the surrounding spins leading to sizable and lasting dynamical spin correlations. In the absence of interactions, these correlations arise solely due to quantum interference. Furthermore, they are both ferromagnetic and antiferromagnetic, in contrast to the equilibrium Nagaoka effect.The interplay of quantum correlations and thermal decoherence is key to understanding the fundamental properties of many-body systems. Coherence is usually easily destroyed by interaction with the environment and local fluctuations inherent to thermal ensembles. Hence experimental demonstrations of many-body quantum correlations rely on cooling the system close to its ground state or pumping it into a well-defined quantum state. Here, the authors instead show how quantum correlations can arise in the opposite limit of an infinite temperature. Motivated by recent experiments with ultracold atoms in optical lattices, they study the dynamics of a hole created in a fermionic or bosonic Mott state in the atomic limit. They demonstrate that the propagating hole entangles the surrounding spins leading to sizable and lasting dynamical spin correlations. In the absence of interactions, these correlations arise solely due to quantum interference. Furthermore, they are both ferromagnetic and antiferromagnetic, in contrast to the equilibrium Nagaoka effect.

arXiv:1703.09231Physical review. B./Physical review. BJul 14, 201737 citations

Ferromagnetic spin correlations in a few-fermion system

P. O. Bugnion, G. J. Conduit

We study the spin correlations of a few fermions in a quasi-one-dimensional trap. Exact diagonalization calculations demonstrate that repulsive interactions between the two species drives ferromagnetic correlations. The ejection probability of an atom provides an experimental probe of the spin correlations. With more than five atoms trapped, the system approaches the itinerant Stoner limit. Losses to Feshbach molecules are suppressed by the discretization of energy levels when fewer than seven atoms are trapped.We study the spin correlations of a few fermions in a quasi-one-dimensional trap. Exact diagonalization calculations demonstrate that repulsive interactions between the two species drives ferromagnetic correlations. The ejection probability of an atom provides an experimental probe of the spin correlations. With more than five atoms trapped, the system approaches the itinerant Stoner limit. Losses to Feshbach molecules are suppressed by the discretization of energy levels when fewer than seven atoms are trapped.

arXiv:1304.3299Physical Review AJun 28, 201351 citations

Local three-spin correlations in the free-fermion and

R. J. Baxter, T. C. CHOYt

Jan 1, 20160 citations

Observation of antiferromagnetic correlations in the Fermi

X. Liu, David A. Huse, Nandini Trivedi

Jan 1, 20130 citations

Measuring spin correlations in optical lattices using superlattice potentials

Kim G. L. Pedersen, Brian M. Andersen, Georg M. Bruun +2 more

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 resulting 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 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.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 resulting 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 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.

arXiv:1105.4466Physical Review AOct 11, 20115 citations

d

-wave pairing, a possible ground-state candidate for the doped repulsive Hubbard model.