Direct interpolative construction of the discrete Fourier transform as a matrix product operator

Fuente: arXiv
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Auteurs principaux: Chen, Jielun, Lindsey, Michael
Format: Preprint
Publié: 2024
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author Chen, Jielun
Lindsey, Michael
author_facet Chen, Jielun
Lindsey, Michael
contents The quantum Fourier transform (QFT), which can be viewed as a reindexing of the discrete Fourier transform (DFT), has been shown to be compressible as a low-rank matrix product operator (MPO) or quantized tensor train (QTT) operator. However, the original proof of this fact does not furnish a construction of the MPO with a guaranteed error bound. Meanwhile, the existing practical construction of this MPO, based on the compression of a quantum circuit, is not as efficient as possible. We present a simple closed-form construction of the QFT MPO using the interpolative decomposition, with guaranteed near-optimal compression error for a given rank. This construction can speed up the application of the QFT and the DFT, respectively, in quantum circuit simulations and QTT applications. We also connect our interpolative construction to the approximate quantum Fourier transform (AQFT) by demonstrating that the AQFT can be viewed as an MPO constructed using a different interpolation scheme.
format Preprint
id arxiv_https___arxiv_org_abs_2404_03182
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Direct interpolative construction of the discrete Fourier transform as a matrix product operator
Chen, Jielun
Lindsey, Michael
Quantum Physics
Numerical Analysis
The quantum Fourier transform (QFT), which can be viewed as a reindexing of the discrete Fourier transform (DFT), has been shown to be compressible as a low-rank matrix product operator (MPO) or quantized tensor train (QTT) operator. However, the original proof of this fact does not furnish a construction of the MPO with a guaranteed error bound. Meanwhile, the existing practical construction of this MPO, based on the compression of a quantum circuit, is not as efficient as possible. We present a simple closed-form construction of the QFT MPO using the interpolative decomposition, with guaranteed near-optimal compression error for a given rank. This construction can speed up the application of the QFT and the DFT, respectively, in quantum circuit simulations and QTT applications. We also connect our interpolative construction to the approximate quantum Fourier transform (AQFT) by demonstrating that the AQFT can be viewed as an MPO constructed using a different interpolation scheme.
title Direct interpolative construction of the discrete Fourier transform as a matrix product operator
topic Quantum Physics
Numerical Analysis
url https://arxiv.org/abs/2404.03182