Quantum steering: device-independent quantification and temporal quantum correlations

  • 陳 信良

Student thesis: Doctoral Thesis

Abstract

Bell nonlocality is one of the most intriguing phenomena in quantum mechanics An important application by using nonlocality of quantum states as a resource is device-independent (DI) quantum information processing which has attracted a lot of attentions recently A main reason is that one can treat the devices as black boxes and few assumptions on the operations of the devices are made Such a black-box scheme makes an experiment feasible even when the devices are imperfect Quantum steering is a phenomenon in quantum theory that allows one party to instantaneously and remotely prepare the set of quantum states for the other spatially separated party merely by the former party’s choice of measurement settings This can not happen in a locally hidden state model from which the measurement outcomes of one party and the quantum states of the other party are predetermined by some hidden variables The resource of such “spooky action at a distance” provides inspirations and many applications in the foundation of quantum mechanics and in quantum information sciences Indeed there exists relations between steering and nonlocality More precisely all nonlocal quantum states are also steerable but not vice versa One of the main works of this thesis is to quantify such a property i e obtaining a lower bound of steerability when given a nonlocal correlations Quantum phenomena can also occur in a single system at different moments of time A famous example is the existence of dynamics which does not fulfill the joint assumption of non-invasive measurability and macroscopic realism This can be witnessed by the violation of a Leggett-Garg inequality which is also treated as a temporal analogue of a Bell inequality Motivated by this we would like to develop a temporal analogue of quantum steering and refer to this new concept as temporal steering which is the other main work of this thesis and several applications are also given
Date of Award2017 Feb 16
Original languageEnglish
SupervisorYueh-Nan Chen (Supervisor)

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