Necessary and Sufficient Condition for Nonzero Quantum Discord

Autor(en)

Borivoje Dakic, Vlatko Vedral, Caslav Brukner

Abstrakt

Quantum discord characterizes “nonclassicality” of correlations in quantum mechanics. It has been proposed as the key resource present in certain quantum communication tasks and quantum computational models without containing much entanglement. We obtain a necessary and sufficient condition for the existence of nonzero quantum discord for any dimensional bipartite states. This condition is easily experimentally implementable. Based on this, we propose a geometrical way of quantifying quantum discord. For two qubits this results in a closed form of expression for discord. We apply our results to the model of deterministic quantum computation with one qubit, showing that quantum discord is unlikely to be the reason behind its speedup.

Organisation(en)

Quantenoptik, Quantennanophysik und Quanteninformation

Externe Organisation(en)

National University of Singapore (NUS), University of Oxford, Österreichische Akademie der Wissenschaften (ÖAW)

Journal

Physical Review Letters

Band

105

Anzahl der Seiten

8

ISSN

0031-9007

DOI

https://doi.org/10.1103/PhysRevLett.105.190502

Publikationsdatum

11-2010

Peer-reviewed

Ja

ÖFOS 2012

103025 Quantenmechanik

Schlagwörter

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/f5050017-334c-40a3-96ea-d92f71b5f2e7