Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Time-Reversed EPR and the Choice of Histories in Quantum Mechanics   When a single photon is split by a beam splitter, its two `halves' can
entangle two distant atoms into an EPR pair. We discuss a time-reversed
analogue of this experiment where two distant sources cooperate so as to emit a
single photon. The two `half photons,' having interacted with two atoms, can
entangle these atoms into an EPR pair once they are detected as a single
photon. Entanglement occurs by creating indistinguishabilility between the two
mutually exclusive histories of the photon. This indistinguishabilility can be
created either at the end of the two histories (by `erasing' the single
photon's path) or at their beginning (by `erasing' the two atoms' positions).

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The categories of this paper are: cond-mat
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The categories of this paper are: alg-geom
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The categories of this paper are: adap-org
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The categories of this paper are: hep-lat
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The categories of this paper are: nlin
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The categories of this paper are: hep-th
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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: solv-int
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The categories of this paper are: math-ph
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The categories of this paper are: comp-gas
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The categories of this paper are: bayes-an
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The categories of this paper are: stat
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The categories of this paper are: supr-con
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The categories of this paper are: physics
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The categories of this paper are: math