Extracting Information from Qubit-Environment Correlations

Reina, John H.; Susa, Cristian E.; Fanchini, Felipe F.

doi:10.1038/srep07443

Cited by 21 publications

(19 citation statements)

References 47 publications

(90 reference statements)

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“…However, a natural strategy to understand the mechanisms underlying these entanglement revivals in the absence of backaction is to perform an in-depth dynamical analysis of the correlation distribution among the parts of such a hybrid quantum-classical composite system, analogously to what is done for quantum dissipative environments [33,35]. We address this investigation by following an information-theoretic point of view.…”

Section: Introductionmentioning

confidence: 99%

“…In the case of local quantum environments, revivals of two-qubit entanglement have been explained by means of periodic entanglement transfers between the qubits and their non-Markovian environments because of the backaction of the environments on the qubits themselves [14,[32][33][34][35]. Differently, in the case of classical environments, which do not backreact on the quantum system and cannot store any quantum correlations, the origin of entanglement revivals appears to be more subtle.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Distributed correlations and information flows within a hybrid multipartite quantum-classical system

Leggio¹,

Franco²,

Soares-Pinto³

et al. 2015

Phys. Rev. A

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Understanding the non-Markovian mechanisms underlying the revivals of quantum entanglement in the presence of classical environments is central in the theory of quantum information. Tentative interpretations have been given by either the role of the environment as a control device or the concept of hidden entanglement. We address this issue from an information-theoretic point of view. To this aim, we consider a paradigmatic tripartite system, already realized in the laboratory, made of two independent qubits and a random classical field locally interacting with one qubit alone. We study the dynamical relationship between the two-qubit entanglement and the genuine tripartite correlations of the overall system, finding that collapse and revivals of entanglement correspond, respectively, to the rise and fall of the overall tripartite correlations. Interestingly, entanglement dark periods can enable plateaux of nonzero tripartite correlations. We then explain this behavior in terms of information flows among the different parties of the system. Besides showcasing the phenomenon of the freezing of overall correlations, our results provide insights on the origin of retrieval of entanglement within a hybrid quantum-classical system.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Distributed correlations and information flows within a hybrid multipartite quantum-classical system

Leggio¹,

Franco²,

Soares-Pinto³

et al. 2015

Phys. Rev. A

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“…2(c), where several distinctive regions can be identified: local - separable (), local-entangled (), and entangled-nonlocal () states (see Methods section). Furthermore, the W - l states also highlight quantum correlations at zero entanglement ( p ≤ 1/3)34, which are captured here by means of the discord353637. Building on this, we take an approach that is not based on entangled7 or nonlocal89 input states.…”

Section: Resultsmentioning

confidence: 99%

Quantum Locality in Game Strategy

Melo-Luna

Susa

Ducuara

et al. 2017

Sci Rep

Self Cite

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Game theory is a well established branch of mathematics whose formalism has a vast range of applications from the social sciences, biology, to economics. Motivated by quantum information science, there has been a leap in the formulation of novel game strategies that lead to new (quantum Nash) equilibrium points whereby players in some classical games are always outperformed if sharing and processing joint information ruled by the laws of quantum physics is allowed. We show that, for a bipartite non zero-sum game, input local quantum correlations, and separable states in particular, suffice to achieve an advantage over any strategy that uses classical resources, thus dispensing with quantum nonlocality, entanglement, or even discord between the players’ input states. This highlights the remarkable key role played by pure quantum coherence at powering some protocols. Finally, we propose an experiment that uses separable states and basic photon interferometry to demonstrate the locally-correlated quantum advantage.

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“…. (17) Note that this rate may turn negative at times for nontrivial spectral densities and therefore the CP map ρ(0) → ρ(t) may lose its divisibility, which is used as an indication for non-Markovian quantum dynamics [9,33,34]. The solution of Eq.…”

Section: Model For System and Environmentmentioning

confidence: 99%

System-environment correlations for dephasing two-qubit states coupled to thermal baths

2016

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Based on the exact dynamics of a two-qubit system and environment, we investigate system-environment (SE) quantum and classical correlations. The coupling is chosen to represent a dephasing channel for one of the qubits and the environment is a proper thermal bath. First we discuss the general issue of dilation for qubit phase damping. Based on the usual thermal bath of harmonic oscillators, we derive criteria of separability and entanglement between an initial X state and the environment. Applying these criteria to initial Werner states, we find that entanglement between the system and environment is built up in time for temperatures below a certain critical temperature T crit . On the other hand, the total state remains separable during those short times that are relevant for decoherence and loss of entanglement in the two-qubit state. Close to T crit the SE correlations oscillate between separable and entangled. Even though these oscillations are also observed in the entanglement between the two qubits, no simple relation between the loss of entanglement in the two-qubit system and the build-up of entanglement between the system and environment is found.

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Extracting Information from Qubit-Environment Correlations

Cited by 21 publications

References 47 publications

Distributed correlations and information flows within a hybrid multipartite quantum-classical system

Distributed correlations and information flows within a hybrid multipartite quantum-classical system

Quantum Locality in Game Strategy

System-environment correlations for dephasing two-qubit states coupled to thermal baths

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