Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Revisit of Antiferromagnetism in Hubbard Model by A Cluster Slave-Spin
  Method   The cluster slave-spin method is introduced to systematically investigate the
solutions of the Hubbard model including the symmetry-broken phases. In this
method, the electron operator is factorized into a fermioninc spinon describing
the physical spin and a slave-spin describing the charge fluctuations.
Following the $U(1)$ formalism derived by Yu and Si [Phys. Rev. B 86, 085104
(2012)], it is shown that the self-consistent equations to explore various
symmetry-broken density wave states can be constructed in general with a
cluster of multiple slave-spin sites. We employ this method to study the
antiferromagnetic (AFM) state in the single band Hubbard model with the two and
four-site clusters of slave spins. While the Hubbard gap, the charge gap due to
the doubly-occupied states, scales with the Hubbard interaction $U$ as
expected, the AFM gap $\Delta$, the gap in the spinon dispersion in the AFM
state, exhibits a crossover from the weak to strong-coupling behaviors as $U$
increases. Our cluster slave-spin method reproduces not only the traditional
mean-field behavior of $\Delta \sim U$ in the weak-coupling limit, but also the
behavior of $\Delta \sim t^2/U$ predicted by the superexchange mechanism in the
strong coupling limit. In addition, the holon-doublon correlator as functions
of $U$ and doping $x$ is also computed, which exhibits a strong tendency toward
the holon-doublon binding in the strong coupling regime. We further show that
the quasiparticle weight obtained by the cluster slave-spin method is in a good
agreement with the generalized Gutzwiller approximation in both AFM and
paramagnetic states, and the results can be improved beyond the generalized
Gutzwiller approximation as the cluster is enlarged from a single site to 4
sites. Our results demonstrate that the cluster slave-spin method can be a
powerful tool to systematically investigate the strongly correlated system.

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The categories of this paper are: nlin
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The categories of this paper are: q-alg
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The categories of this paper are: stat
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The categories of this paper are: hep-ph
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The categories of this paper are: solv-int
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The categories of this paper are: physics
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The categories of this paper are: math-ph
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The categories of this paper are: q-bio
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The categories of this paper are: funct-an
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The categories of this paper are: chao-dyn
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The categories of this paper are: atom-ph
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The categories of this paper are: gr-qc
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The categories of this paper are: nucl-ex
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The categories of this paper are: comp-gas
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The categories of this paper are: mtrl-th
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The categories of this paper are: acc-phys