Distillation of local purity from quantum states

Recently Horodecki et al. [Phys. Rev. Lett. 90, 100402 (2003)] introduced an important quantum information processing paradigm in which two parties sharing many copies of the same bipartite quantum state distill local pure states by means of local unitary operations assisted by a one-way (two-way) completely dephasing channel. Local pure states are a valuable resource from a thermodynamical point of view since they allow thermal energy to be converted into work by local quantum heat engines. The work deficit was defined as the decrease in the work extractable from the joint system due to this process of localization, and was proposed as a measure of the quantumness of correlations. We give a simple information theoretical characterization of the one-way work deficit, which turns out to be complementary to a previously known operational measure of classical correlations, the one-way distillable common randomness