Record number :
1207183
Title of article :
Quantum discord with weak measurements Original Research Article
Author/Authors :
Uttam Singh، نويسنده , , Arun Kumar Pati، نويسنده ,
Issue Information :
روزنامه با شماره پیاپی سال 2014
Pages :
12
From page :
141
To page :
152
Abstract :
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 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 measurement. Moreover, we prove the monotonicity of the super quantum discord as a function of the measurement strength and in the limit of strong projective measurement the super quantum discord becomes the normal quantum discord. We find that unlike the normal discord, for pure entangled states, the super quantum discord can exceed the quantum entanglement. Our results provide new insights on the nature of quantum correlation and suggest that the notion of quantum correlation is not only observer dependent but also depends on how weakly one perturbs the composite system. We illustrate the key results for pure as well as mixed entangled states.
Keywords :
Projective measurement , Weak measurement , Quantum discord
Journal title :
Annals of Physics
Serial Year :
2014
Link To Document :
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