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

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

doi:10.1103/physrevb.90.054304

Cited by 104 publications

(79 citation statements)

References 88 publications

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“…The use of either DD techniques or non-Markovian effects prolongs the preservation of both entanglement and discord in presence of environmental noise [31][32][33][34][35]. However, studies of single qubit dynamics have recently shown that the simultaneous use of non-Markovian reservoir engineering and DD protocols is counterproductive for coherence preservation [7].…”

Section: Introductionmentioning

confidence: 99%

Time-invariant discord in dynamically decoupled systems

2015

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Dynamical decoupling protocols are one of the most used tools for efficient quantum error corrections and for reservoir engineering. In this paper we study the effect of dynamical decoupling pulses on the preservation of both quantum and classical correlations, and their influence on the intriguing phenomenon of time-invariant discord. We study two qubits experiencing local dephasing with an Ohmic class spectrum and subject to dynamical decoupling protocols. We investigate the connection between the dynamics of both classical and quantum correlations and the behaviour of information flow between system and environment. Finally, we establish a set of necessary conditions for which time-invariant discord can be created using dynamically decoupling techniques.

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Section: Introductionmentioning

confidence: 99%

Time-invariant discord in dynamically decoupled systems

2015

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“…Despite this, two all-optical experiments have already confirmed that quantum entanglement can either spontaneously revive [22] or be recovered by local operations [31] in non-Markovian classical environments. Few tentative explanations have been provided so far: one relies on the role played by the classical environment as a control mechanism which, thanks to the memory effect, keeps a record for what operation has been applied to the quantum system [21,22]; another one is based on the concept of hidden entanglement, that is, the amount of quantum correlations not revealed by the density matrix description of the system state that can surface by means of local operations [30,31,36].…”

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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“…Similarly to PDD, the gate error under CP is weakly dependent on γ M (the quasi-static approximation is valid until γ M ≤ . On the other side, the gate performance under UDD is the very sensitive to the high-frequency (soft) cut-off of the noise, analogously to other analysis 23,66 .…”

Section: Carr-purcell and Uhrig Dynamical Decouplingmentioning

confidence: 99%

“…Recently, the lifetime of an entangled state of a superconducting flux qubit coupled to a microscopic two-level fluctuator has been enhanced by DD techniques 52 . Entanglement preservation between independent qubits (storage) from local pure dephasing random-telegraph and 1/f noise by dynamical decoupling has been predicted 53,54 and demonstrated in an all-optical experiment 55 .…”

Section: Introductionmentioning

confidence: 99%

High-fidelity two-qubit gates via dynamical decoupling of local1/fnoise at the optimal point

D’Arrigo¹,

Falci²,

Paladino³

2016

Phys. Rev. A

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We investigate the possibility to achieve high-fidelity universal two-qubit gates by supplementing optimal tuning of individual qubits with dynamical decoupling (DD) of local 1/f noise. We consider simultaneous local pulse sequences applied during the gate operation and compare the efficiencies of periodic, Carr-Purcell and Uhrig DD with hard π-pulses along two directions (π z/y pulses). We present analytical perturbative results (Magnus expansion) in the quasi-static noise approximation combined with numerical simulations for realistic 1/f noise spectra. The gate efficiency is studied as a function of the gate duration, of the number n of pulses, and of the high-frequency roll-off. We find that the gate error is non-monotonic in n, decreasing as n −α in the asymptotic limit, α ≥ 2 depending on the DD sequence. In this limit πz-Urhig is the most efficient scheme for quasi-static 1/f noise, but it is highly sensitive to the soft UV-cutoff. For small number of pulses, πz control yields anti-Zeno behavior, whereas πy pulses minimize the error for a finite n. For the current noise figures in superconducting qubits, two-qubit gate errors ∼ 10 −6 , meeting the requirements for fault-tolerant quantum computation, can be achieved. The Carr-Purcell-Meiboom-Gill sequence is the most efficient procedure, stable for 1/f noise with UV-cutoff up to gigahertz.

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

Cited by 104 publications

References 88 publications

Time-invariant discord in dynamically decoupled systems

Time-invariant discord in dynamically decoupled systems

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

High-fidelity two-qubit gates via dynamical decoupling of local1/fnoise at the optimal point

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