Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: High-fidelity entanglement swapping and generation of three-qubit GHZ
  state using asynchronous telecom photon pair sources   We experimentally demonstrate a high-fidelity entanglement swapping and a
generation of the Greenberger-Horne-Zeilinger~(GHZ) state using
polarization-entangled photon pairs at telecommunication wavelength produced by
spontaneous parametric down conversion with continuous-wave pump light. While
spatially separated sources asynchronously emit photon pairs, the time-resolved
photon detection guarantees the temporal indistinguishability of photons
without active timing synchronizations of pump lasers and/or adjustment of
optical paths. In the experiment, photons are sufficiently narrowed by
fiber-based Bragg gratings with the central wavelengths of 1541~nm and 1580~nm,
and detected by superconducting nanowire single-photon detectors with low
timing jitters. Observed fidelities are 0.84 \pm 0.04 and 0.70 \pm 0.05 for the
entanglement swapping and generation of the GHZ state, respectively.

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The categories of this paper are: hep-ph
31
The categories of this paper are: ao-sci
11
The categories of this paper are: hep-lat
3
The categories of this paper are: physics
24
The categories of this paper are: dg-ga
34
The categories of this paper are: chem-ph
27
The categories of this paper are: comp-gas
36
The categories of this paper are: cmp-lg
33
The categories of this paper are: plasm-ph
32
The categories of this paper are: atom-ph
8
The categories of this paper are: hep-ex
4
The categories of this paper are: cond-mat
16
The categories of this paper are: stat
1
The categories of this paper are: cs
30
The categories of this paper are: q-alg
26
The categories of this paper are: bayes-an