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arXiv · 1304.0741

Faster Phase Estimation

Krysta M. Svore·Matthew B. Hastings·Michael Freedman
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Abstract

We develop several algorithms for performing quantum phase estimation based on basic measurements and classical post-processing. We present a pedagogical review of quantum phase estimation and simulate the algorithm to numerically determine its scaling in circuit depth and width. We show that the use of purely random measurements requires a number of measurements that is optimal up to constant factors, albeit at the cost of exponential classical post-processing; the method can also be used to improve classical signal processing. We then develop a quantum algorithm for phase estimation that yields an asymptotic improvement in runtime, coming within a factor of log* of the minimum number of measurements required while still requiring only minimal classical post-processing. The corresponding quantum circuit requires asymptotically lower depth and width (number of qubits) than quantum phase estimation.

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Krysta M. Svore, Matthew B. Hastings, Michael Freedman. 2013-04-02. Faster Phase Estimation. https://arxiv.org/abs/1304.0741

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