Optimized Dynamical Decoupling Sequences in Protecting Two-Qubit States

Abstract

Aperiodic dynamical decoupling (DD) sequences of $\pi$ pulses are of great interest to decoherence control and have been recently extended from single-qubit to two-qubit systems. If the environmental noise power spectrum is made available, then one may further optimize aperiodic DD sequences to reach higher efficiency of decoherence suppression than known universal schemes. This possibility is investigated in this work for the protection of two-qubit states, using an exactly solvable pure dephasing model including both local and nonlocal noise. The performance of optimized DD sequences in protecting two-qubit states is compared with that achieved by nested Uhrig's DD (nested-UDD) sequences, for several different types of noise spectrum. Except for cases with noise spectrum decaying slowly in the high-frequency regime, optimized DD sequences with tens of control pulses can perform orders of magnitude better than that of nested-UDD. A two-qubit system with highly unbalanced local noise is also examined to shed more light on a recent experiment. Possible experiments that may be motivated by this work are discussed.

9 pages, two figures

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Cited by in corpus (12)

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• Preserving entanglement and nonlocality in solid-state qubits by dynamical decoupling
• Robustness of dynamical decoupling sequences
• Spectroscopy of cross-correlations of environmental noises with two qubits
• Decoherence control: Universal protection of two-qubit states and two-qubit gates using continuous driving fields
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• Engineered Decoherence: Characterization and Suppression
• Higher-order protection of quantum gates: Hamiltonian engineering coordinated with dynamical decoupling