Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Polaron Variational Methods In The Particle Representation Of Field
  Theory : II. Numerical Results For The Propagator   For the scalar Wick-Cutkosky model in the particle representation we perform
a similar variational calculation for the 2-point function as was done by
Feynman for the polaron problem. We employ a quadratic nonlocal trial action
with a retardation function for which several ans\"atze are used. The
variational parameters are determined by minimizing the variational function
and in the most general case the nonlinear variational equations are solved
numerically. We obtain the residue at the pole, study analytically and
numerically the instability of the model at larger coupling constants and
calculate the width of the dressed particle.

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The categories of this paper are: math
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The categories of this paper are: adap-org
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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: q-fin
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The categories of this paper are: acc-phys
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The categories of this paper are: astro-ph
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The categories of this paper are: patt-sol
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The categories of this paper are: funct-an
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The categories of this paper are: mtrl-th
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The categories of this paper are: bayes-an
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The categories of this paper are: ao-sci
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The categories of this paper are: quant-ph
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The categories of this paper are: eess
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The categories of this paper are: alg-geom
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The categories of this paper are: math-ph