Necessary and Sufficient Condition for Nonzero Quantum Discord
- Author(s)
- Borivoje Dakic, Vlatko Vedral, Caslav Brukner
- Abstract
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(s)
- Quantum Optics, Quantum Nanophysics and Quantum Information
- External organisation(s)
- National University of Singapore (NUS), University of Oxford, Österreichische Akademie der Wissenschaften (ÖAW)
- Journal
- Physical Review Letters
- Volume
- 105
- No. of pages
- 8
- ISSN
- 0031-9007
- DOI
- https://doi.org/10.1103/PhysRevLett.105.190502
- Publication date
- 11-2010
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 103025 Quantum mechanics
- Keywords
- Portal url
- https://ucrisportal.univie.ac.at/en/publications/f5050017-334c-40a3-96ea-d92f71b5f2e7