Experimental quantum computing without entanglement.
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TLDR
The results show that even fully separable, highly mixed, states can contain intrinsically quantum mechanical correlations and that these could offer a valuable resource for quantum information technologies.Abstract:
Deterministic quantum computation with one pure qubit (DQC1) is an efficient model of computation that uses highly mixed states. Unlike pure-state models, its power is not derived from the generation of a large amount of entanglement. Instead it has been proposed that other nonclassical correlations are responsible for the computational speedup, and that these can be captured by the quantum discord. In this Letter we implement DQC1 in an all-optical architecture, and experimentally observe the generated correlations. We find no entanglement, but large amounts of quantum discord-except in three cases where an efficient classical simulation is always possible. Our results show that even fully separable, highly mixed, states can contain intrinsically quantum mechanical correlations and that these could offer a valuable resource for quantum information technologies.read more
Citations
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The classical-quantum boundary for correlations: Discord and related measures
TL;DR: Different methods for quantifying the quantum and classical parts of correlations are among the more actively studied topics of quantum-information theory over the past decade as mentioned in this paper and different notions of classical and quantum correlations quantified by quantum discord and other related measures are reviewed.
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Quantum discord for two-qubit X states
TL;DR: In this article, the authors derived explicit expressions for quantum discord for a larger class of two-qubit states, namely, a seven-parameter family of so called X states that have been of interest in a variety of contexts in the field.
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Unified View of Quantum and Classical Correlations
TL;DR: This work discusses the problem of the separation of total correlations in a given quantum state into entanglement, dissonance, and classical correlations using the concept of relative entropy as a distance measure of correlations.
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Photonic Boson Sampling in a Tunable Circuit
Matthew A. Broome,Alessandro Fedrizzi,Saleh Rahimi-Keshari,Justin Dove,Scott Aaronson,Timothy C. Ralph,Andrew White +6 more
TL;DR: The central premise of boson sampling was tested, experimentally verifying that three-photon scattering amplitudes are given by the permanents of submatrices generated from a unitary describing a six-mode integrated optical circuit.
Journal ArticleDOI
Robustness of quantum discord to sudden death
TL;DR: In this paper, the dissipative dynamics of two-qubit quantum discord under Markovian environments were analyzed, and it was shown that quantum discord is more robust than the entanglement against decoherence.
References
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