Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Experimental demonstration of a heralded entanglement source   The heralded generation of entangled states is a long-standing goal in
quantum information processing, because it is indispensable for a number of
quantum protocols. Polarization entangled photon pairs are usually generated
through spontaneous parametric down-conversion, but the emission is
probabilistic. Their applications are generally accompanied by post-selection
and destructive photon detection. Here, we report a source of entanglement
generated in an event-ready manner by conditioned detection of auxiliary
photons. This scheme benefits from the stable and robust properties of
spontaneous parametric down-conversion and requires only modest experimental
efforts. It is flexible and allows the preparation efficiency to be
significantly improved by using beamsplitters with different transmission
ratios. We have achieved a fidelity better than 87% and a state preparation
efficiency of 45% for the source. This could offer promise in essential
photonics-based quantum information tasks, and particularly in enabling optical
quantum computing by reducing dramatically the computational overhead.

33
The categories of this paper are: plasm-ph
10
The categories of this paper are: q-bio
19
The categories of this paper are: eess
35
The categories of this paper are: mtrl-th
23
The categories of this paper are: solv-int
30
The categories of this paper are: q-alg
18
The categories of this paper are: econ
21
The categories of this paper are: adap-org
3
The categories of this paper are: physics
27
The categories of this paper are: comp-gas
29
The categories of this paper are: funct-an
36
The categories of this paper are: cmp-lg
8
The categories of this paper are: hep-ex
6
The categories of this paper are: astro-ph
4
The categories of this paper are: cond-mat
2
The categories of this paper are: math