Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: String Picture of Bose-Einstein Condensation   A nonrelativistic Bose gas is represented as a grand-canonical ensemble of
fluctuating closed spacetime strings of arbitrary shape and length. The loops
are characterized by their string tension and the number of times they wind
around the imaginary time axis. At the temperature where Bose-Einstein
condensation sets in, the string tension, being determined by the chemical
potential, vanishes, the system becomes critical, and the strings proliferate.
A comparison with Feynman's description in terms of rings of cyclicly permuted
bosons shows that the winding number of a loop corresponds to the number of
particles contained in a ring.

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The categories of this paper are: econ
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The categories of this paper are: alg-geom
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The categories of this paper are: acc-phys
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The categories of this paper are: chao-dyn
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The categories of this paper are: quant-ph
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The categories of this paper are: gr-qc
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The categories of this paper are: mtrl-th
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The categories of this paper are: nlin
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The categories of this paper are: math
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The categories of this paper are: solv-int
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The categories of this paper are: physics
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The categories of this paper are: dg-ga
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The categories of this paper are: hep-th
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The categories of this paper are: nucl-ex
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The categories of this paper are: cs
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The categories of this paper are: hep-ex