Optimality of Gaussian Discord
Abstract
In this Letter we exploit the recently solved conjecture on the bosonic minimum output entropy to show the optimality of Gaussian discord, so that the computation of quantum discord for bipartite Gaussian states can be restricted to local Gaussian measurements. We prove such optimality for a large family of Gaussian states, including all twomode squeezed thermal states, which are the most typical Gaussian states realized in experiments. Our family also includes other types of Gaussian states and spans their entire set in a suitable limit where they become Choi matrices of Gaussian channels. As a result, we completely characterize the quantum correlations possessed by some of the most important bosonic states in quantum optics and quantum information.
 Publication:

Physical Review Letters
 Pub Date:
 October 2014
 DOI:
 10.1103/PhysRevLett.113.140405
 arXiv:
 arXiv:1309.2215
 Bibcode:
 2014PhRvL.113n0405P
 Keywords:

 03.65.Ta;
 03.67.Mn;
 42.50.p;
 Foundations of quantum mechanics;
 measurement theory;
 Entanglement production characterization and manipulation;
 Quantum optics;
 Quantum Physics;
 Condensed Matter  Statistical Mechanics;
 Mathematical Physics;
 Physics  Optics
 EPrint:
 ReVTEX. 4 pages + 6 pages (Supplemental Material)