Interference and Measurement: Changing amplitude phase information to amplitude magnitude information

Fuente: arXiv
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Main Authors: Agarwal, Pranjal, Ali, Nada, Hillery, Mark
Format: Preprint
Published: 2025
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author Agarwal, Pranjal
Ali, Nada
Hillery, Mark
author_facet Agarwal, Pranjal
Ali, Nada
Hillery, Mark
contents There are quantum procedures that encode the solutions to a problem in the phases of quantum amplitudes. This happens in some quantum optimization algorithms in which the value of a function to be maximized or minimized is represented by a phase. An example of this is the QAOA algorithm for the MaxCut problem in which one encodes the number of edges connecting the sets resulting from a partition of the vertices of a graph into phases of amplitudes of a quantum state. Another is the minimum vertex cover problem in which the number of edges included in the cover is encoded in phases. Here we want to see what can be done if we only use simple aspects of quantum mechanics, interference and measurement, to manipulate the magnitudes of the amplitudes whose phases encode the relevant information. The idea is to use constructive interference to enhance the amplitudes that contain useful information and destructive interference to suppress those that do not. We examine examples, both analytically and numerically. We also show how the results of sequences of measurements can be used to gain information about the landscape of solutions.
format Preprint
id arxiv_https___arxiv_org_abs_2502_14793
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Interference and Measurement: Changing amplitude phase information to amplitude magnitude information
Agarwal, Pranjal
Ali, Nada
Hillery, Mark
Quantum Physics
There are quantum procedures that encode the solutions to a problem in the phases of quantum amplitudes. This happens in some quantum optimization algorithms in which the value of a function to be maximized or minimized is represented by a phase. An example of this is the QAOA algorithm for the MaxCut problem in which one encodes the number of edges connecting the sets resulting from a partition of the vertices of a graph into phases of amplitudes of a quantum state. Another is the minimum vertex cover problem in which the number of edges included in the cover is encoded in phases. Here we want to see what can be done if we only use simple aspects of quantum mechanics, interference and measurement, to manipulate the magnitudes of the amplitudes whose phases encode the relevant information. The idea is to use constructive interference to enhance the amplitudes that contain useful information and destructive interference to suppress those that do not. We examine examples, both analytically and numerically. We also show how the results of sequences of measurements can be used to gain information about the landscape of solutions.
title Interference and Measurement: Changing amplitude phase information to amplitude magnitude information
topic Quantum Physics
url https://arxiv.org/abs/2502.14793