Uttam Singh, Arun Kumar Pati
Weak measurements cause small change to quantum states, thereby opening up the possibility of new ways of manipulating and controlling quantum systems. We ask, can weak measurements reveal more quantumness? In particular, can they lead to more quantum correlation in a composite quantum state? We prove that the weak measurement induced quantum discord, called as the "super quantum discord", is always larger than the quantum discord captured by the strong measurements. Unlike the normal quantum discord, for pure entangled states, the super quantum discord can exceed the quantum entanglement. We argue that the super quantum discord can be potentially a more useful resource. As an application, we show that the super discord can result in an improvement on the entropic uncertainty relation in the presence of quantum memory.
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http://arxiv.org/abs/1211.0939
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