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DOE OSTI · 22080368

Quadratic dynamical decoupling: Universality proof and error analysis

Kuo, Wan-Jung·Lidar, Daniel A
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Abstract

We prove the universality of the generalized QDD{sub N{sub 1N{sub 2}}} (quadratic dynamical decoupling) pulse sequence for near-optimal suppression of general single-qubit decoherence. Earlier work showed numerically that this dynamical decoupling sequence, which consists of an inner Uhrig DD (UDD) and outer UDD sequence using N{sub 1} and N{sub 2} pulses, respectively, can eliminate decoherence to O(T{sup N}) using O(N{sup 2}) unequally spaced ''ideal'' (zero-width) pulses, where T is the total evolution time and N=N{sub 1}=N{sub 2}. A proof of the universality of QDD has been given for even N{sub 1}. Here we give a general universality proof of QDD for arbitrary N{sub 1} and N{sub 2}. As in earlier proofs, our result holds for arbitrary bounded environments. Furthermore, we explore the single-axis (polarization) error suppression abilities of the inner and outer UDD sequences. We analyze both the single-axis QDD performance and how the overall performance of QDD depends on the single-axis errors. We identify various performance effects related to the parities and relative magnitudes of N{sub 1} and N{sub 2}. We prove that using QDD{sub N{sub 1N{sub 2}}} decoherence can always be eliminated to O(T{sup min{l_brace}N{sub 1},N{sub 2}{r_brace}}).

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71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICSDECOUPLINGERRORSPARITYPOLARIZATIONPULSESQUANTUM DECOHERENCEQUBITSSPINSPIN ECHO

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Kuo, Wan-Jung, Lidar, Daniel A. 2011-10-15. Quadratic dynamical decoupling: Universality proof and error analysis. https://doi.org/10.1103/physreva.84.042329

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