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

Abstract

In this paper we study how to preserve entanglement and nonlocality under dephasing produced by classical noise with large low-frequency components, as $1/f$ noise, by 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 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.

12 pages, 8 figures

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Cited by in corpus (4)

• Experimental on-demand recovery of entanglement by local operations within non-Markovian dynamics
• Harnessing non-Markovian quantum memory by environmental coupling
• Dynamics of entanglement of two electron spins interacting with nuclear spin baths in quantum dots
• Role of complementary correlations in the evolution of classical and quantum correlations under Markovian decoherence