Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Thermal Properties of Interacting Bose Fields and Imaginary-Time
  Stochastic Differential Equations   Matsubara Green's functions for interacting bosons are expressed as classical
statistical averages corresponding to a linear imaginary-time stochastic
differential equation. This makes direct numerical simulations applicable to
the study of equilibrium quantum properties of bosons in the non-perturbative
regime. To verify our results we discuss an oscillator with quartic
anharmonicity as a prototype model for an interacting Bose gas. An analytic
expression for the characteristic function in a thermal state is derived and a
Higgs-type phase transition discussed, which occurs when the oscillator
frequency becomes negative.

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The categories of this paper are: cs
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The categories of this paper are: q-fin
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The categories of this paper are: gr-qc
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The categories of this paper are: math-ph
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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: astro-ph
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The categories of this paper are: hep-ph
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The categories of this paper are: quant-ph
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The categories of this paper are: physics
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The categories of this paper are: ao-sci
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The categories of this paper are: dg-ga
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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: adap-org
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The categories of this paper are: mtrl-th