Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Method for Solving the Bloch Equation from the Connection with
  Time-Dependent Oscillator   We introduce a novel method to find exact density operators for a spin-1/2
particle in time-dependent magnetic fields by using the one-mode bosonic
representation of $su(2)$ and the connection with a time-dependent oscillator.
As illustrative examples, we apply the method to find the density operators for
constant and/or oscillating magnetic fields, which turn out to be
time-dependent in general.

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The categories of this paper are: chem-ph
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The categories of this paper are: chao-dyn
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The categories of this paper are: funct-an
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The categories of this paper are: ao-sci
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The categories of this paper are: plasm-ph
2
The categories of this paper are: math
3
The categories of this paper are: physics
11
The categories of this paper are: hep-lat
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The categories of this paper are: patt-sol
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The categories of this paper are: eess
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The categories of this paper are: dg-ga
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The categories of this paper are: adap-org
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The categories of this paper are: q-bio
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The categories of this paper are: mtrl-th
5
The categories of this paper are: gr-qc
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The categories of this paper are: hep-th