Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Van der Waals loops and the melting transition in two dimensions   Evidence for the existence of van der Waals loops in pressure p versus volume
v plots has for some time supported the belief that melting in two dimensions
is a first order phase transition. We report rather accurate equilibrium p(v)
curves for systems of hard disks obtained from long Monte Carlo simulations.
These curves, obtained in the constant volume ensemble, using periodic boundary
conditions, exhibit well defined van der Waals loops. We illustrate their
existence for finite systems that are known to undergo a continuous transition
in the thermodynamic limit. To this end, we obtain magnetization m versus
applied field curves from Monte Carlo simulations of the 2D Ising model, in the
constant m ensemble, at the critical point. Whether van der Waals loops for
disk systems behave in the thermodynamic limit as they do for the 2D Ising
model at the critical point cannot be ruled out. Thus, the often made claim
that melting in 2D is a first order phase transition, based on the evidence
that van der Waals loops exist, is not sound.

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The categories of this paper are: adap-org
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The categories of this paper are: chem-ph
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The categories of this paper are: gr-qc
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The categories of this paper are: supr-con
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The categories of this paper are: econ
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The categories of this paper are: stat
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The categories of this paper are: hep-ex
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The categories of this paper are: quant-ph
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The categories of this paper are: q-bio
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The categories of this paper are: eess
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The categories of this paper are: mtrl-th
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The categories of this paper are: comp-gas
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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: q-fin
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The categories of this paper are: bayes-an