Abstract

Few studies explored the dynamics of nonclassical correlations besides entanglement in open multipartite quantum systems. Here, we address the time evolution of quantum discord and entanglement in a model of three noninteracting qubits subject to a classical random telegraph noise in common and separated environments. Two initial entangled states of the system are examined, namely the GHZ- and W-type states. The dynamics of quantum correlations results to be strongly affected by the input configuration of the qubits, the type of the system-environment interaction, and the memory properties of the environmental noise. When the qubits are nonlocally coupled to the random telegraph noise, the GHZ-type states partially preserve, at long times, both discord and entanglement, regardless of the correlation time of the environmental noise. The survived entangled states turn out to be also detectable by means of suitable entanglement witnesses. On the other hand, in the same conditions, the decohering effects suppress all the quantum correlation of the W-type states which are thus less robust than the GHZ-type ones. The long-time survival of tripartite discord and entanglement opens interesting perspectives in the use of multipartite entangled states for practical applications in quantum information science.

Highlights

  • Entanglement is a peculiar feature of quantum mechanics which constitutes a valuable resource for a number of features of quantum information processing, such as quantum communication, cryptography, and computation [1]

  • Many research efforts focused on the investigation of the decoherence processes and of the dynamics of entanglement in different quantum systems ranging from quantum optics [3–6] to nanophysics [7]

  • Multipartite entanglement has been investigated by means of suitable entanglement witnesses (EWs), namely observables that can detect the presence of the entanglement itself [12–14]

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Summary

INTRODUCTION

Entanglement is a peculiar feature of quantum mechanics which constitutes a valuable resource for a number of features of quantum information processing, such as quantum communication, cryptography, and computation [1]. [26] involves difficult extremization procedures over operators or states which makes the calculations very hard This justifies the scarse number of works exploring the time evolution of quantum correlations in multipartite open systems. This gives us the chance to analyze how the local or non-local nature of the qubits-environment coupling and the memory properties of the environment itself affect the dynamics of quantum correlation and its possible sudden death, revival, or trapping From this point of view, the choice of a classical environment does not represent a strict constraint of the model, since a quantum environment not affected by the system or influenced in a way that does not result in back-action, can be mimicked by a classical noise [32] that was already shown to be able to lead, in bipartite systems, to sudden death and revival of entanglement and discord [28, 31, 33].

Tripartite Quantum Discord
Tripartite Negativity
Entanglement Witnesses
THE MODEL
Different Environments
RESULTS
Common Environment
W-type states
CONCLUSIONS

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