Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Effect of Doublon-Holon Binding on Mott transition---Variational Monte
  Carlo Study of Two-Dimensional Bose Hubbard Models   To understand the mechanism of Mott transitions in case of no magnetic
influence, superfluid-insulator (Mott) transitions in the S=0 Bose Hubbard
model at unit filling are studied on the square and triangular lattices, using
a variational Monte Carlo method. In trial many-body wave functions, we
introduce various types of attractive correlation factors between a
doubly-occupied site (doublon, D) and an empty site (holon, H), which play a
central role for Mott transitions, in addition to the onsite repulsive
(Gutzwiller) factor. By optimizing distance-dependent parameters, we study
various properties of this type of wave functions. With a hint from the Mott
transition arising in a completely D-H bound state, we propose an improved
picture of Mott transitions, by introducing two characteristic length scales,
the D-H binding length $\xi_{\rm dh}$ and the minimum D-D exclusion length
$\xi_{\rm dd}$. Generally, a Mott transition occurs when $\xi_{\rm dh}$ becomes
comparable to $\xi_{\rm dd}$. In the conductive (superfluid) state, domains of
D-H pairs overlap with each other ($\xi_{\rm dh}>\xi_{\rm dd}$); thereby D and
H can propagate independently as density carriers by successively exchanging
the partners. In contrast, intersite repulsive Jastrow (D-D and H-H) factors
have little importance for the Mott transition.

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The categories of this paper are: funct-an
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The categories of this paper are: q-alg
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The categories of this paper are: q-bio
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The categories of this paper are: cs
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The categories of this paper are: math-ph
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The categories of this paper are: acc-phys
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The categories of this paper are: quant-ph
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The categories of this paper are: nucl-ex
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The categories of this paper are: hep-ph
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The categories of this paper are: gr-qc
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The categories of this paper are: hep-lat
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The categories of this paper are: cmp-lg
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The categories of this paper are: chao-dyn
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The categories of this paper are: physics
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The categories of this paper are: plasm-ph
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The categories of this paper are: econ