Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Classical and Quantum Action-Phase Variables for Time-Dependent
  Oscillators   For a time-dependent classical quadratic oscillator we introduce pairs of
real and complex invariants that are linear in position and momentum. Each pair
of invariants realize explicitly a canonical transformation from the phase
space to the invariant space, in which the action-phase variables are defined.
We find the action operator for the time-dependent oscillator via the
classical-quantum correspondence. Candidate phase operators conjugate to the
action operator are discussed, but no satisfactory ones are found.

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The categories of this paper are: physics
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The categories of this paper are: adap-org
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The categories of this paper are: plasm-ph
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The categories of this paper are: comp-gas
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The categories of this paper are: chem-ph
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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: cond-mat
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The categories of this paper are: astro-ph
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The categories of this paper are: patt-sol
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The categories of this paper are: solv-int
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The categories of this paper are: stat
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The categories of this paper are: nucl-ex
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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: nucl-th