Entanglement dynamics in superconducting qubits affected by local bistable impurities

Franco, Rosario Lo; D’Arrigo, A.; Falci, G.; Compagno, G.; Paladino, E.

doi:10.1088/0031-8949/2012/t147/014019

Cited by 64 publications

(63 citation statements)

References 21 publications

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“…For larger values of g, the numerical ESD and FD times are reported in Table I. The dependence of the single-qubit coherence q s (t) on the initial population difference δp 0,s qualitatively affects the entanglement dynamics for g >ḡ, while it leaves it practically unchanged for g ḡ [72]. In particular, when g >ḡ, the concurrence for δp 0 = ±1 does not exhibit revivals, and it is always larger than for δp 0 = 0.…”

Section: A Entanglement Under Local Rtnmentioning

confidence: 99%

Preserving entanglement and nonlocality in solid-state qubits by dynamical decoupling

et al. 2014

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In this paper, we study how to preserve entanglement and nonlocality under dephasing produced by classical noise with large low-frequency components, such as 1/f noise, using dynamical decoupling techniques. We first show that quantifiers of entanglement and nonlocality satisfy a closed relation valid for two independent qubits locally coupled to a generic environment under pure dephasing and starting from a general class of initial states. This result allows us to assess the efficiency of pulse-based dynamical decoupling for protecting nonlocal quantum correlations between two qubits subject to pure-dephasing local random telegraph and 1/f noise. We investigate the efficiency of an "entanglement memory" element under two-pulse echo and under sequences of periodic, Carr-Purcell, and Uhrig dynamical decoupling. The Carr-Purcell sequence is shown to outperform the other sequences in preserving entanglement against both random telegraph and 1/f noise. For typical 1/f flux-noise figures in superconducting nanocircuits, we show that entanglement and its nonlocal features can be efficiently stored up to times one order of magnitude longer than natural entanglement disappearance times employing pulse timings of current experimental reach.

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Section: A Entanglement Under Local Rtnmentioning

confidence: 99%

Preserving entanglement and nonlocality in solid-state qubits by dynamical decoupling

et al. 2014

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“…The RTN is generated from a bistable fluctuator flipping between two values with a switching rate ξ. RTN allows one to model environmental noise appearing in many semiconducting and superconducting nanodevices [32][33][34][35][36][37]. Noises with 1/f α spectra are found when the environment can be described as a collection of N f random bistable fluctuators, with N f ≥ 1.…”

Section: Introductionmentioning

confidence: 99%

Non-Markovianity of colored noisy channels

2014

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We address the non-Markovian character of quantum maps describing the interaction of a qubit with a random classical field. In particular, we evaluate trace-and capacity-based non-Markovianity measures for two relevant classes of environments showing non-Gaussian fluctuations, described respectively by random telegraph noise and colored noise with spectra of the the form 1/f α . We analyze the dynamics of both the trace distance and the quantum capacity, and show that the behavior of non-Markovianity based on both measures is qualitatively similar. Our results show that environments with a spectrum that contains a relevant low-frequency contribution are generally non-Markovian. We also find that the non-Markovianity of colored environments decreases when the number of fluctuators realizing the environment increases.

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“…The utilization of quantum correlations, like entanglement, nonlocality, and discord, is in fact jeopardized by the detrimental effects of the environment surrounding the quantum system [6][7][8][9][10][11][12] so that finding strategies to preserve them has become a main requirement. Non-Markovian noise, originating from structured environments or from strong couplings [4][5][6]13], has been shown to enable dynamical revivals of quantum correlations independently of the quantum [8,[14][15][16][17] or classical [18][19][20][21][22][23][24][25][26][27][28][29][30][31] nature of the environment, allowing an extension of their exploitation time. It is therefore of basic interest to understand the origin of these revival phenomenons.…”

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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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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Entanglement dynamics in superconducting qubits affected by local bistable impurities

Cited by 64 publications

References 21 publications

Preserving entanglement and nonlocality in solid-state qubits by dynamical decoupling

Preserving entanglement and nonlocality in solid-state qubits by dynamical decoupling

Non-Markovianity of colored noisy channels

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

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