Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Macroscopic evolution of mechanical and thermal energy in a harmonic
  chain with random flip of velocities   We consider an unpinned chain of harmonic oscillators with periodic boundary
conditions, whose dynamics is perturbed by a random flip of the sign of the
velocities. The dynamics conserves the total volume (or elongation) and the
total energy of the system. We prove that in a diffusive space-time scaling
limit the profiles corresponding to the two conserved quantities converge to
the solution of a diffusive system of differential equations. While the
elongation follows a simple autonomous linear diffusive equation, the evolution
of the energy depends on the gradient of the square of the elongation.

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The categories of this paper are: nucl-th
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The categories of this paper are: acc-phys
3
The categories of this paper are: physics
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The categories of this paper are: econ
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The categories of this paper are: eess
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The categories of this paper are: hep-th
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The categories of this paper are: chao-dyn
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The categories of this paper are: gr-qc
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The categories of this paper are: dg-ga
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The categories of this paper are: q-alg
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The categories of this paper are: q-bio
33
The categories of this paper are: plasm-ph
35
The categories of this paper are: mtrl-th
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The categories of this paper are: stat
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The categories of this paper are: ao-sci
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The categories of this paper are: cmp-lg