Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Dirac's Quantum Phase Problem   In 1927 the great physicist Paul A. M. Dirac failed to provide a consistent
quantum description of the phase of a radiation field. Only one year later, he
developed the famous Dirac theory of the electron, which led to the
anti-particle -- the positron. We show that the reason for Dirac's failure with
the phase problem bears a striking resemblance to his ingenious insight into
the nature of the electron. For a correct quantum description of the phase of a
radiation field it is necessary to take the polarisation into account.
Similarly to the introduction of the anti-particle of the electron, the
inclusion of the second polarisation resolves the inconsistency of the quantum
phase problem. This also leads to new insight into the quantum measurement
problem of time.

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The categories of this paper are: cmp-lg
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The categories of this paper are: supr-con
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The categories of this paper are: plasm-ph
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The categories of this paper are: atom-ph
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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: ao-sci
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The categories of this paper are: alg-geom
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The categories of this paper are: dg-ga
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The categories of this paper are: mtrl-th
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The categories of this paper are: math-ph
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The categories of this paper are: cond-mat
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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: q-fin
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The categories of this paper are: q-bio