Quantum Rational Transformation Using Linear Combinations of Hamiltonian Simulations

Fuente: arXiv
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Hauptverfasser: Shen, Yizhi, Van Buggenhout, Niel, Camps, Daan, Klymko, Katherine, Van Beeumen, Roel
Format: Preprint
Veröffentlicht: 2024
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author Shen, Yizhi
Van Buggenhout, Niel
Camps, Daan
Klymko, Katherine
Van Beeumen, Roel
author_facet Shen, Yizhi
Van Buggenhout, Niel
Camps, Daan
Klymko, Katherine
Van Beeumen, Roel
contents Rational functions are exceptionally powerful tools in scientific computing, yet their abilities to advance quantum algorithms remain largely untapped. In this paper, we introduce effective implementations of rational transformations of a target operator on quantum hardware. By leveraging suitable integral representations of the operator resolvent, we show that rational transformations can be performed efficiently with Hamiltonian simulations using a linear-combination-of-unitaries (LCU). We formulate two complementary LCU approaches, discrete-time and continuous-time LCU, each providing unique strategies to decomposing the exact integral representations of a resolvent. We consider quantum rational transformation for the ubiquitous task of approximating functions of a Hermitian operator, with particular emphasis on the elementary signum function. For illustration, we discuss its application to the ground and excited state problems. Combining rational transformations with observable dynamic mode decomposition (ODMD), our recently developed noise-resilient quantum eigensolver, we design a fully real-time approach for resolving many-body spectra. Our numerical demonstration on spin systems indicates that our real-time framework is compact and achieves accurate estimation of the low-lying energies.
format Preprint
id arxiv_https___arxiv_org_abs_2408_07742
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Quantum Rational Transformation Using Linear Combinations of Hamiltonian Simulations
Shen, Yizhi
Van Buggenhout, Niel
Camps, Daan
Klymko, Katherine
Van Beeumen, Roel
Quantum Physics
Rational functions are exceptionally powerful tools in scientific computing, yet their abilities to advance quantum algorithms remain largely untapped. In this paper, we introduce effective implementations of rational transformations of a target operator on quantum hardware. By leveraging suitable integral representations of the operator resolvent, we show that rational transformations can be performed efficiently with Hamiltonian simulations using a linear-combination-of-unitaries (LCU). We formulate two complementary LCU approaches, discrete-time and continuous-time LCU, each providing unique strategies to decomposing the exact integral representations of a resolvent. We consider quantum rational transformation for the ubiquitous task of approximating functions of a Hermitian operator, with particular emphasis on the elementary signum function. For illustration, we discuss its application to the ground and excited state problems. Combining rational transformations with observable dynamic mode decomposition (ODMD), our recently developed noise-resilient quantum eigensolver, we design a fully real-time approach for resolving many-body spectra. Our numerical demonstration on spin systems indicates that our real-time framework is compact and achieves accurate estimation of the low-lying energies.
title Quantum Rational Transformation Using Linear Combinations of Hamiltonian Simulations
topic Quantum Physics
url https://arxiv.org/abs/2408.07742