Universal pulse sequence to minimize spin dephasing in the central spin decoherence problem

Abstract

We present a remarkable finding that a recently discovered [G. S. Uhrig, Phys. Rev. Lett. 98, 100504 (2007)] series of pulse sequences, designed to optimally restore coherence to a qubit in the spin-boson model of decoherence, is in fact completely model-independent and generically valid for arbitrary dephasing Hamiltonians given sufficiently short delay times between pulses. The series maximizes qubit fidelity versus number of applied pulses for sufficiently short delay times because the series, with each additional pulse, cancels successive orders of a time expansion for the fidelity decay. The "magical" universality of this property, which was not appreciated earlier, requires that a linearly growing set of "unknowns" (the delay times) must simultaneously satisfy an exponentially growing set of nonlinear equations that involve arbitrary dephasing Hamiltonian operators.

Published in PRL, revised

References in corpus (7)

• Fault-Tolerant Quantum Dynamical Decoupling
• Performance of Deterministic Dynamical Decoupling Schemes: Concatenated and Periodic Pulse Sequences
• Restoring Coherence Lost to a Slow Interacting Mesoscopic Bath
• Concatenated dynamical decoupling in a solid-state spin bath
• Decoherence induced by anisotropic hyperfine interaction in Si spin qubits
• Optimization of Short Coherent Control Pulses
• Wavefunction considerations for the central spin decoherence problem in a nuclear spin bath

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• How to Enhance Dephasing Time in Superconducting Qubits
• Quantum many-body theory of qubit decoherence in a finite-size spin bath
• Universality of Uhrig dynamical decoupling for suppressing qubit pure dephasing and relaxation
• Exact Results on Dynamical Decoupling by $\pi$-Pulses in Quantum Information Processes
• Pure quantum dephasing of a solid state electron spin qubit in a large nuclear spin bath coupled by long-range hyperfine-mediated interactions
• Nuclear Spins in Nanostructures
• Concatenated Control Sequences based on Optimized Dynamic Decoupling
• Rigorous Bounds on the Performance of a Hybrid Dynamical Decoupling-Quantum Computing Scheme
• Quantum decoherence of a charge qubit in a spin-fermion model
• Numerical Analysis of Optimized Coherent Control Pulses