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arXiv · 1508.07524

A Simple Derivation of the Fong-Wandzura Pulse Sequence

Daniel Zeuch·N. E. Bonesteel
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Abstract

We give an analytic construction of a class of two-qubit gate pulse sequences that act on five of the six spin-$\frac12$ particles used to encode a pair of exchange-only three-spin qubits. Within this class, the problem of gate construction reduces to that of finding a smaller sequence that acts on four spins and is subject to a simple constraint. The optimal sequence satisfying this constraint yields a two-qubit gate sequence equivalent to that found numerically by Fong and Wandzura. Our construction is sufficiently simple that it can be carried out entirely with pen, paper, and knowledge of a few basic facts about quantum spin. We thereby analytically derive the Fong-Wandzura sequence that has so far escaped intuitive explanation.

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BibTeXRIS

Daniel Zeuch, N. E. Bonesteel. 2015-08-30. A Simple Derivation of the Fong-Wandzura Pulse Sequence. https://doi.org/10.1103/physreva.93.010303

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