Operational Resource Theory of Coherence.
TLDR
An operational theory of coherence (or of superposition) in quantum systems is established, by focusing on the optimal rate of performance of certain tasks, by demonstrating that the coherence theory is generically an irreversible theory by a simple criterion that completely characterizes all reversible states.Abstract:
We establish an operational theory of coherence (or of superposition) in quantum systems, by focusing on the optimal rate of performance of certain tasks. Namely, we introduce the two basic concepts-"coherence distillation" and "coherence cost"-in the processing quantum states under so-called incoherent operations [Baumgratz, Cramer, and Plenio, Phys. Rev. Lett. 113, 140401 (2014)]. We, then, show that, in the asymptotic limit of many copies of a state, both are given by simple single-letter formulas: the distillable coherence is given by the relative entropy of coherence (in other words, we give the relative entropy of coherence its operational interpretation), and the coherence cost by the coherence of formation, which is an optimization over convex decompositions of the state. An immediate corollary is that there exists no bound coherent state in the sense that one would need to consume coherence to create the state, but no coherence could be distilled from it. Further, we demonstrate that the coherence theory is generically an irreversible theory by a simple criterion that completely characterizes all reversible states.read more
Citations
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Unification of quantum resources in distributed scenarios
TL;DR: This work extends the single party coherence resource framework to the distributed scenario and relates it to basis-dependent discord, and shows the operational meaning of basis- dependent discord in quantum key distribution.
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Quantifying quantum coherence based on the generalized alpha-z-relative Rényi entropy
TL;DR: This work presents a family of coherence quantifiers based on the generalizedalpha–z-relative R that satisfy all the standard criteria for well-defined measures ofCoherence and include some existing coherence measures as special cases.
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Quantifying the imaginarity of quantum mechanics
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TL;DR: In this article, the authors introduce a resource theoretic framework for imaginarity, where the free states are taken to be those with density matrices that are real with respect to a fixed basis.
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Direct estimation of quantum coherence by collective measurements
Yuan Yuan,Yuan Yuan,Zhibo Hou,Jun-Feng Tang,Alexander Streltsov,Guo-Yong Xiang,Chuan-Feng Li,Guang-Can Guo +7 more
TL;DR: In this paper, a collective measurement scheme for estimating the amount of coherence in quantum states, which requires entangled measurements on two copies of the state, was proposed, leading to higher precision in a large parameter range for estimating established coherence quantifiers of qubit and qutrit states.
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Enhancing nonlocal advantage of quantum coherence in correlated quantum channels
Yu-Xia Xie,Zhi-Yong Qin +1 more
TL;DR: Analysis of decay behaviors of the nonlocal advantage of quantum coherence (NAQC) for two qubits traversing the phase flap, bit flip, bit-phase flip, and depolarizing channels shows analytically that the NAQC of the output states can always be noticeably enhanced.
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