Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Hourglass - Consequences of Pure Hamiltonian Evolution of a
  Radiating System   Hourglass is the name given here to a formal isolated quantum system that can
radiate. Starting from a time when it defines the system it represents clearly
and no radiation is present, it is given straightforward Hamiltonian evolution.
The question of what significance hourglasses have is raised, and this question
is proposed to be more consequential than the measurement problem.

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The categories of this paper are: mtrl-th
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The categories of this paper are: eess
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The categories of this paper are: acc-phys
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The categories of this paper are: funct-an
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The categories of this paper are: q-alg
6
The categories of this paper are: astro-ph
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The categories of this paper are: bayes-an
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The categories of this paper are: chem-ph
7
The categories of this paper are: hep-th
5
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: chao-dyn
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The categories of this paper are: adap-org
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The categories of this paper are: econ
33
The categories of this paper are: plasm-ph
17
The categories of this paper are: q-fin