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

2016/05/20 by A. D'Arrigo, A. D’Arrigo, G. Falci +2
Computer Science · Mathematics · Physics and Astronomy · #Algorithm #Combinatorics #Computer science #Dynamical decoupling #Mathematics #Noise (video) #Physics #Quantum #Quantum Computing Algorithms and Architecture #Quantum Information and Cryptography #Quantum and electron transport phenomena #Quantum computer #Quantum mechanics #Qubit #Topology (electrical circuits) #cond-mat.supr-con #quant-ph

paper · pdf · doi:10.1103/physreva.94.022303

11 pages, 9 figures

arxiv created 2016/05/20 · openalex created_date 2016/06/24 · openalex publication_date 2016/08/03 · arxiv updated 2016/08/24 · openalex updated_date 2026/08/05

Abstract

We investigate the possibility of achieving 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 \ensuremathπ pulses along two directions (\ensuremathπ_z/y pulses). We present analytical perturbative results (Magnus expansion) in the quasistatic 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 nonmonotonic in n, decreasing as n^\ensuremath-\ensuremathα in the asymptotic limit, \ensuremathα\ensuremath≥2, depending on the DD sequence. In this limit \ensuremathπ_z-Urhig is the most efficient scheme for quasistatic 1/f noise, but it is highly sensitive to the soft UV cutoff. For small number of pulses, \ensuremathπ_z control yields anti-Zeno behavior, whereas \ensuremathπ_y pulses minimize the error for a finite n. For the current noise figures in superconducting qubits, two-qubit gate errors \ensuremath∼10^\ensuremath-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.

Citations

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