Quantum algorithms for learning and learning algorithms for quantum

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Abstract/Contents

Abstract
Machine learning has established itself as one of the most successful computational paradigms of the 21st century. Quantum computation is attempting to be the next one. What algorithmic and theoretical insights can each of these fields gain from the other? We first apply the tools of machine learning and its theoretical counterpart, computational learning theory, to a famously resource-intensive operation at the heart of quantum experiments: quantum state tomography. It is the following task: given many identically-prepared copies of the same n-qubit quantum state, output an approximation of its density matrix, which has 2^n numbers. We consider performing adaptive measurements on the state. We design a neural network that `learns to learn' the correct measurement, which also speeds up a previous proposal for adaptive Bayesian updates in tomography by a factor of a million for a realistic situation. Theorists have also considered relaxing the requirement, in tomography, to output an approximation of the full density matrix -- and have proposed learning models in which, the learner need only predict the state's acceptance probability on measurements. We show that many of these ``reduced" learning models are information-theoretically related. Finally, we switch gears: instead of applying the lessons of learning theory to quantum mechanics, we do the reverse. We develop a quantum algorithm for what is considered the ``quantum" version of Bayes' rule -- the Petz recovery channel. As a byproduct, we also obtain an algorithm for implementing pretty-good measurements. Ours is the first systematic prescription to implement these ubiquitous theoretical tools in quantum error correction and quantum algorithms on a quantum computer.

Description

Type of resource text
Form electronic resource; remote; computer; online resource
Extent 1 online resource.
Place California
Place [Stanford, California]
Publisher [Stanford University]
Copyright date 2021; ©2021
Publication date 2021; 2021
Issuance monographic
Language English

Creators/Contributors

Author Quek, Yihui
Degree supervisor Mabuchi, Hideo
Degree supervisor Weissman, Tsachy
Thesis advisor Mabuchi, Hideo
Thesis advisor Weissman, Tsachy
Thesis advisor Wilde, Mark M
Degree committee member Wilde, Mark M
Associated with Stanford University, Department of Applied Physics

Subjects

Genre Theses
Genre Text

Bibliographic information

Statement of responsibility Yihui Quek.
Note Submitted to the Department of Applied Physics.
Thesis Thesis Ph.D. Stanford University 2021.
Location https://purl.stanford.edu/hh334vn9663

Access conditions

Copyright
© 2021 by Yihui Quek
License
This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).

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