Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Observation of antiferromagnetic correlations in the Hubbard model with
  ultracold atoms   Ultracold atoms in optical lattices have great potential to contribute to a
better understanding of some of the most important issues in many-body physics,
such as high-$T_c$ superconductivity. The Hubbard model describes many of the
features shared by the copper oxides, including an interaction-driven Mott
insulating state and an antiferromagnetic (AFM) state. Optical lattices filled
with a two-spin-component Fermi gas of ultracold atoms can faithfully realise
the Hubbard model with readily tunable parameters, and thus provide a platform
for the systematic exploration of its phase diagram. Realisation of strongly
correlated phases, however, has been hindered by the need to cool the atoms to
temperatures as low as the magnetic exchange energy, and also by the lack of
reliable thermometry. Here we demonstrate spin-sensitive Bragg scattering of
light to measure AFM spin correlations in a realisation of the 3D Hubbard model
at temperatures down to 1.4 times that of the AFM phase transition. This
temperature regime is beyond the range of validity of a simple high-temperature
series expansion, which brings our experiment close to the limit of the
capabilities of current numerical techniques. We reach these low temperatures
using a unique compensated optical lattice technique, in which the confinement
of each lattice beam is compensated by a blue-detuned laser beam. The
temperature of the atoms in the lattice is deduced by comparing the light
scattering to determinantal quantum Monte Carlo and numerical linked-cluster
expansion calculations. Further refinement of the compensated lattice may
produce even lower temperatures which, along with light scattering thermometry,
would open avenues for achieving and characterising other novel quantum states
of matter, such as the pseudogap regime of the 2D Hubbard model.

22
The categories of this paper are: chao-dyn
8
The categories of this paper are: hep-ex
16
The categories of this paper are: stat
34
The categories of this paper are: chem-ph
14
The categories of this paper are: math-ph
1
The categories of this paper are: cs
11
The categories of this paper are: hep-lat
13
The categories of this paper are: quant-ph
5
The categories of this paper are: gr-qc
6
The categories of this paper are: astro-ph
12
The categories of this paper are: nucl-th
30
The categories of this paper are: q-alg
27
The categories of this paper are: comp-gas
7
The categories of this paper are: hep-th
2
The categories of this paper are: math
35
The categories of this paper are: mtrl-th