Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Exotic phase diagram of a cluster charging model of bosons on the kagome
  lattice   We study a model of hard-core bosons on the kagome lattice with short-range
hopping ($t$) and repulsive interactions ($V$). This model directly maps on to
an easy-axis $S=1/2$ XXZ model on the kagome lattice and is also related, at
large $V/t$, to a quantum dimer model on the triangular lattice. Using quantum
Monte Carlo (QMC) numerics, we map out the phase diagram of this model at
half-filling. At T=0, we show that this model exhibits a superfluid phase at
small $V/t$ and an insulating phase at large $V/t$, separated by a continuous
quantum phase transition at $V_c/t \approx 19.8$. The insulating phase at T=0
appears to have no conventional broken symmetries, and is thus a uniform Mott
insulator (a `spin liquid' in magnetic language). We characterize this
insulating phase as a uniform $Z_2$ fractionalized insulator from the
topological order in the ground state and estimate its vison gap. Consistent
with this identification, there is no apparent thermal phase transition upon
heating the insulator. The insulating phase instead smoothly crosses over into
the high temperature paramagnet via an intermediate cooperative paramagnetic
regime. We also study the superfluid-to-normal thermal transition for $V <
V_c$. We find that this is a Kosterlitz-Thouless transition at small $V/t$ but
changes to a first order transition for $V$ closer to $V_c$. We argue that this
first order thermal transition is consistent with the presence of a nearby
$Z_2$ insulating ground state obtained from the superfluid ground state by
condensing double vortices.

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The categories of this paper are: adap-org
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The categories of this paper are: nucl-ex
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The categories of this paper are: cmp-lg
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The categories of this paper are: plasm-ph
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The categories of this paper are: econ
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The categories of this paper are: bayes-an
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The categories of this paper are: patt-sol
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The categories of this paper are: dg-ga
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The categories of this paper are: funct-an
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The categories of this paper are: math
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The categories of this paper are: math-ph
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The categories of this paper are: nucl-th
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The categories of this paper are: nlin
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The categories of this paper are: stat
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The categories of this paper are: eess
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The categories of this paper are: q-alg