Quantum analytic descent

Variational algorithms have particular relevance for near-term quantum computers but require nontrivial parameter optimizations. Here we propose analytic descent: Given that the energy landscape must have a certain simple form in the local region around any reference point, it can be efficiently app...

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Bibliographic Details
Main Authors: Bálint Koczor, Simon C. Benjamin
Format: Article
Language:English
Published: American Physical Society 2022-04-01
Series:Physical Review Research
Online Access:http://doi.org/10.1103/PhysRevResearch.4.023017
Description
Summary:Variational algorithms have particular relevance for near-term quantum computers but require nontrivial parameter optimizations. Here we propose analytic descent: Given that the energy landscape must have a certain simple form in the local region around any reference point, it can be efficiently approximated in its entirety by a classical model—we support these observations with rigorous, complexity-theoretic arguments. One can classically analyze this approximate function to directly jump to the (estimated) minimum before determining a more refined function, if necessary. We derive an optimal measurement strategy and generally prove that the asymptotic resource cost of a jump corresponds to only a single gradient vector evaluation.
ISSN:2643-1564