منابع مشابه
Quantum feedback with weak measurements
The problem of feedback control of quantum systems by means of weak measurements is investigated in detail. When weak measurements are made on a set of identical quantum systems, the single-system density matrix can be determined to a high degree of accuracy while affecting each system only slightly. If this information is fed back into the systems by coherent operations, the single-system dens...
متن کاملQuantum discord for Gaussian states with non-Gaussian measurements
Paolo Giorda,1 Michele Allegra,1,2,3 and Matteo G. A. Paris4,5 1Institute for Scientific Interchange Foundation (ISI), I-10126 Torino, Italy 2Dipartimento di Fisica, Università di Torino, I-10125 Torino, Italy 3INFN, Sezione di Torino, I-10125 Torino, Italy 4Dipartimento di Fisica, Università degli Studi di Milano, I-20133 Milano, Italy 5CNISM, Unità di Milano, I-20133 Milano, Italy (Received 1...
متن کاملQuantum discord in quantum computation
Quantum discord is a measure of the quantumness of correlations. After reviewing its different versions and properties, we apply it to the questions of quantum information processing. First we show that changes in discord in the processed unentangled states indicate the need for entanglement in the distributed implementation of quantum gates. On the other hand, it was shown that zero system-env...
متن کاملGaussian quantum discord.
We extend the quantum discord to continuous variable systems and evaluate Gaussian quantum discord C(ϱ) for bipartite Gaussian states. In particular, for squeezed-thermal states, we explicitly maximize the extractable information over Gaussian measurements: C(ϱ) is minimized by a generalized measurement rather than a projective one. Almost all squeezed-thermal states have nonzero Gaussian disco...
متن کاملGeometric quantum discord with Bures distance
We define a new measure of quantum correlations in bipartite quantum systems given by the Bures distance of the system state to the set of classical states with respect to one subsystem, that is, to the states with zero quantum discord. Our measure is a geometrical version of the quantum discord. As the latter it quantifies the degree of non-classicality in the system. For pure states it is ide...
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ژورنال
عنوان ژورنال: Annals of Physics
سال: 2014
ISSN: 0003-4916
DOI: 10.1016/j.aop.2014.02.004