Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Bushes of vibrational modes for Fermi-Pasta-Ulam chains   Some exact solutions and multi-mode invariant submanifolds were found for the
Fermi-Pasta-Ulam (FPU) beta-model by Poggi and Ruffo in Phys. D 103 (1997) 251.
In the present paper we demonstrate how results of such a type can be obtained
for an arbitrary N-particle chain with periodic boundary conditions with the
aid of our group-theoretical approach [Phys. D 117 (1998) 43] based on the
concept of bushes of normal modes for mechanical systems with discrete
symmetry. The integro-differential equation describing the FPU-alfa dynamics in
the modal space is derived. The loss of stability of the bushes of modes for
the FPU-alfa model, in particular, for the limiting case N >> 1 for the
dynamical regime with displacement pattern having period twice the lattice
spacing (Pi-mode) is studied. Our results for the FPU-alfa chain are compared
with those by Poggi and Ruffo for the FPU-beta chain.

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The categories of this paper are: atom-ph
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The categories of this paper are: chao-dyn
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The categories of this paper are: math
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The categories of this paper are: acc-phys
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The categories of this paper are: eess
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The categories of this paper are: econ
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The categories of this paper are: nucl-ex
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The categories of this paper are: funct-an
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The categories of this paper are: q-fin
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The categories of this paper are: supr-con
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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: stat
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The categories of this paper are: gr-qc
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The categories of this paper are: bayes-an
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The categories of this paper are: q-bio