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arXiv · 1212.2427

Quantum discord in nuclear magnetic resonance systems at room temperature

J. Maziero·R. Auccaise·L. C. Celeri·D. O. Soares-Pinto·E. R. deAzevedo·T. J. Bonagamba·R. S. Sarthour·I. S. Oliveira·R. M. Serra
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Abstract

We review the theoretical and the experimental aspects regarding the quantification and identification of quantum correlations in liquid-state nuclear magnetic resonance (NMR) systems at room temperature. We start by introducing a formal method to obtain the quantum discord and its classical counterpart in systems described by a deviation matrix. Next, we apply such a method to experimentally demonstrate that the peculiar dynamics, with a sudden change behaviour, of quantum discord under decoherence, theoretically predicted only for phase-noise channels, is also present even under the effect of a thermal environment. This result shows that such a phenomena are much stronger than we could think, at principle. Walking through a different path, we discuss an observable witness for the quantumness of correlations in two-qubit systems and present the first experimental implementation of such a quantity in a NMR setup. Such a witness could be very useful in situations were the knowledge of the nature of correlations (in contrast of how much correlations) presented in a given state is enough.

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J. Maziero, R. Auccaise, L. C. Celeri, D. O. Soares-Pinto, E. R. deAzevedo, T. J. Bonagamba, R. S. Sarthour, I. S. Oliveira, R. M. Serra. 2012-12-11. Quantum discord in nuclear magnetic resonance systems at room temperature. https://doi.org/10.1007/s13538-013-0118-1

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