Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Problem of Ground State in Thermo-Field Dynamics   Analytic continuation of quantum statistical physics from imaginary to real
time is analyzed. Adiabatic vanishing of interactions at real time infinities
gives origin to singularities at complex times. This undermines the hypothesis
of decoupling of interactions at $t \rightarrow \infty$. Hence an interacting
thermal vacuum is a necessary component of the exact real-time formalism.
Consequences for Thermo-field dynamics are discussed.

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The categories of this paper are: gr-qc
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The categories of this paper are: stat
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The categories of this paper are: quant-ph
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The categories of this paper are: chao-dyn
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The categories of this paper are: solv-int
26
The categories of this paper are: bayes-an
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The categories of this paper are: eess
31
The categories of this paper are: ao-sci
1
The categories of this paper are: cs
12
The categories of this paper are: nucl-th
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The categories of this paper are: alg-geom
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The categories of this paper are: funct-an
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The categories of this paper are: chem-ph
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The categories of this paper are: cond-mat
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The categories of this paper are: adap-org
18
The categories of this paper are: econ