Quantum correlations in predictive processes

(Received 18 April 2013; published 17 June 2013)We consider the role of quantum correlations in the efficient use of information by a predictive quantumsystem, generalizing a recently proposed classical measure of nonpredictive information to the quantum regime.We show that, as a quantum system changes state, the nonpredictive information held by another correlatedquantum system is exactly equal to the extractable work that is lost from the second system. We use quantumdiscord to quantify the quantum contribution, and demonstrate the possibility of improved thermodynamicefficiency due to a negative “quantum part” of the lost work. We also give a thermodynamic interpretation toquantum discord, as the reduction in extractable work under an optimal classical approximation of a quantummemory.DOI: 10.1103/PhysRevA.87.060302 PACS number(s): 03 .67.−a, 89.70.−a, 03.65.Yz, 05.70.Ln