Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Onset of Chaos in the Quantum Hard-Sphere Gas   We show that the condition for the appearance of quantum chaos (Wigner-Dyson
distribution of energy eigenvalues, gaussian-random energy eigenfunctions) in a
dilute gas of many hard spheres is $\lambda \ll \ell$, where $\lambda$ is the
wavelength of a typical particle and $\ell$ is the mean free path between
collisions. For fermions with Fermi wavelength $\lambda_F \ll \ell$, this
implies that all energy eigenstates, including the ground state, are chaotic.
Physical implications are discussed.

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The categories of this paper are: stat
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The categories of this paper are: q-bio
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The categories of this paper are: astro-ph
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The categories of this paper are: hep-lat
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The categories of this paper are: funct-an
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The categories of this paper are: patt-sol
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The categories of this paper are: econ
35
The categories of this paper are: mtrl-th
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The categories of this paper are: gr-qc
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The categories of this paper are: acc-phys
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The categories of this paper are: comp-gas
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The categories of this paper are: adap-org
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The categories of this paper are: hep-ex
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The categories of this paper are: bayes-an
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The categories of this paper are: supr-con
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The categories of this paper are: chem-ph