KTH/Nordita/SU seminar in Theoretical Physics [before December 2013]
Wednesday 10 November 2010
to 12:00 at
Caslav Brukner (Wien)
Quantum discord characterizes "non-classicality" 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. I will show give a necessary and sufficient condition for the existence of non-zero quantum discord for any dimensional bipartite states. This condition is easily experimentally implementable. Based on this, I will give a geometrical way of quantifying quantum discord. For two qubits this results in a closed form of expression for discord. I will 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.