Improved Quantum Algorithms for Eigenvalues Finding and Gradient Descent

Fuente: arXiv
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Main Authors: Nghiem, Nhat A., Wei, Tzu-Chieh
Format: Preprint
Published: 2023
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author Nghiem, Nhat A.
Wei, Tzu-Chieh
author_facet Nghiem, Nhat A.
Wei, Tzu-Chieh
contents Block encoding is a key ingredient in the recently developed quantum singular value transformation (QSVT) framework, which provides a unifying description for many quantum algorithms. Initially introduced to simplify and optimize resource utilization in various problems, such as searching, amplitude estimation, and Hamiltonian simulation, it is reasonable to expect that the capabilities of QSVT extend beyond these applications and offer untapped potential for designing new quantum algorithms. In this article, we affirm this perspective by leveraging block encoding to substantially enhance two previously proposed quantum algorithms: largest eigenvalue estimation and quantum gradient descent. Unlike previous works that rely on sophisticated approaches, our findings demonstrate that even just elementary operations within the unitary block encoding framework can eliminate major scaling factors present in their original counterparts. This results in significantly more efficient quantum algorithms capable of tackling target computational problems with remarkable efficiency. Furthermore, we illustrate how our proposed method can be extended to other contexts, including matrix inversion and multiple eigenvalue estimation.
format Preprint
id arxiv_https___arxiv_org_abs_2312_14786
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Improved Quantum Algorithms for Eigenvalues Finding and Gradient Descent
Nghiem, Nhat A.
Wei, Tzu-Chieh
Quantum Physics
Block encoding is a key ingredient in the recently developed quantum singular value transformation (QSVT) framework, which provides a unifying description for many quantum algorithms. Initially introduced to simplify and optimize resource utilization in various problems, such as searching, amplitude estimation, and Hamiltonian simulation, it is reasonable to expect that the capabilities of QSVT extend beyond these applications and offer untapped potential for designing new quantum algorithms. In this article, we affirm this perspective by leveraging block encoding to substantially enhance two previously proposed quantum algorithms: largest eigenvalue estimation and quantum gradient descent. Unlike previous works that rely on sophisticated approaches, our findings demonstrate that even just elementary operations within the unitary block encoding framework can eliminate major scaling factors present in their original counterparts. This results in significantly more efficient quantum algorithms capable of tackling target computational problems with remarkable efficiency. Furthermore, we illustrate how our proposed method can be extended to other contexts, including matrix inversion and multiple eigenvalue estimation.
title Improved Quantum Algorithms for Eigenvalues Finding and Gradient Descent
topic Quantum Physics
url https://arxiv.org/abs/2312.14786