Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Verification of quantum discord   We introduce a measurement-based method for verifying quantum discord of any
bipartite quantum system. We show that by performing an informationally
complete POVM (IC-POVM) on one subsystem and checking the commutativity of the
conditional states of the other subsystem, quantum discord from the second
subsystem to the first can be verified. This is an improvement upon previous
methods, which enables us to efficiently apply our method to
continuous-variable systems, as IC-POVMs are readily available from homodyne or
heterodyne measurements. We show that quantum discord for Gaussian states can
be verified by checking whether the peaks of the conditional Wigner functions
corresponding to two different outcomes of heterodyne measurement coincide at
the same point in the phase space. Using this method, we also prove that the
only Gaussian states with zero discord are product states; hence, Gaussian
states with Gaussian discord have nonzero quantum discord.

8
The categories of this paper are: hep-ex
32
The categories of this paper are: atom-ph
36
The categories of this paper are: cmp-lg
27
The categories of this paper are: comp-gas
6
The categories of this paper are: astro-ph
24
The categories of this paper are: dg-ga
2
The categories of this paper are: math
14
The categories of this paper are: math-ph
28
The categories of this paper are: alg-geom
29
The categories of this paper are: funct-an
5
The categories of this paper are: gr-qc
34
The categories of this paper are: chem-ph
9
The categories of this paper are: nlin
31
The categories of this paper are: ao-sci
0
The categories of this paper are: hep-ph
1
The categories of this paper are: cs