Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Magnetic and pair correlations of the Hubbard model with
  next-nearest-neighbor hopping   A combination of analytical approaches and quantum Monte Carlo simulations is
used to study both magnetic and pairing correlations for a version of the
Hubbard model that includes second-neighbor hopping $t^{\prime }=-0.35t$ as a
model for high-temperature superconductors. Magnetic properties are analyzed
using the Two-Particle Self-Consistent approach. The maximum in magnetic
susceptibility as a function of doping appears both at finite $% t^{\prime }$
and at $t^{\prime }=0$ but for two totally different physical reasons. When
$t^{\prime }=0$, it is induced by antiferromagnetic correlations while at
$t^{\prime }=-0.35t$ it is a band structure effect amplified by interactions.
Finally, pairing fluctuations are compared with $% T $-matrix results to
disentangle the effects of van Hove singularity and of nesting on
superconducting correlations. The addition of antiferromagnetic fluctuations
increases slightly the $d$-wave superconducting correlations despite the
presence of a van Hove singularity which tends to decrease them in the
repulsive model. Some aspects of the phase diagram and some subtleties of
finite-size scaling in Monte Carlo simulations, such as inverted finite-size
dependence, are also discussed.

6
The categories of this paper are: astro-ph
10
The categories of this paper are: q-bio
7
The categories of this paper are: hep-th
23
The categories of this paper are: solv-int
33
The categories of this paper are: plasm-ph
22
The categories of this paper are: chao-dyn
24
The categories of this paper are: dg-ga
19
The categories of this paper are: eess
5
The categories of this paper are: gr-qc
34
The categories of this paper are: chem-ph
16
The categories of this paper are: stat
31
The categories of this paper are: ao-sci
1
The categories of this paper are: cs
11
The categories of this paper are: hep-lat
18
The categories of this paper are: econ
15
The categories of this paper are: nucl-ex