Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Greenberger-Horne-Zeilinger-type violation of local realism by mixed
  states   Cluster states are multi-particle entangled states with special entanglement
properties particularly suitable for quantum computation. It has been shown
that cluster states can exhibit Greenberger-Horne-Zeilinger (GHZ)-type
non-locality even when some of their qubits have been lost. In the present
work, we generated a four-photon mixed state, which is equivalent to the
partial, qubit-loss state of an N-qubit cluster state up to some local
transformations. By using this mixed state, we then realize a GHZ-type
violation of local realism. Our results not only demonstrate a mixed state's
GHZ-type non-locality but also exhibit the robustness of cluster states under
qubit-loss conditions.

9
The categories of this paper are: nlin
23
The categories of this paper are: solv-int
28
The categories of this paper are: alg-geom
32
The categories of this paper are: atom-ph
19
The categories of this paper are: eess
37
The categories of this paper are: supr-con
36
The categories of this paper are: cmp-lg
21
The categories of this paper are: adap-org
24
The categories of this paper are: dg-ga
3
The categories of this paper are: physics
5
The categories of this paper are: gr-qc
10
The categories of this paper are: q-bio
14
The categories of this paper are: math-ph
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