Quantum-accelerated conjugate gradient method via spectral initialization

Fuente: arXiv
Guardado en:
Detalles Bibliográficos
Autores principales: Miyashita, Shigetora, Shimada, Yoshi-aki
Formato: Preprint
Publicado: 2026
Materias:
Acceso en línea:
Etiquetas: Agregar Etiqueta
Sin Etiquetas, Sea el primero en etiquetar este registro!
_version_ 1866915934395957248
author Miyashita, Shigetora
Shimada, Yoshi-aki
author_facet Miyashita, Shigetora
Shimada, Yoshi-aki
contents Solving large-scale linear systems problems is a cornerstone in scientific and industrial computing. Classical iterative solvers face increasing difficulty as the number of unknowns becomes large, while fully quantum linear solvers require fault-tolerant resources that remain far beyond near-term feasibility. Here we propose a quantum-accelerated conjugate gradient (QACG) method in which a fault-tolerant quantum algorithm is used exclusively to construct a spectrally informed initial guess for a classical conjugate gradient (CG) solver. We estimate the total runtime and resource requirements of an integrated quantum-HPC platform for the 3D Poisson equation. A central feature of QACG is the controllable decomposition of the condition number between the quantum and the classical solver, enabling flexible allocation of computational effort. Under explicit architectural assumptions, we identify regimes in which QACG yields a runtime advantage over purely classical approaches while requiring substantially fewer quantum resources than end-to-end quantum linear solvers. These results illustrate a concrete pathway toward the scientific and industrial use of early-stage fault-tolerant quantum computing and point to a integrated paradigm in which quantum devices act as accelerators within high-performance computing workflows.
format Preprint
id arxiv_https___arxiv_org_abs_2602_09696
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Quantum-accelerated conjugate gradient method via spectral initialization
Miyashita, Shigetora
Shimada, Yoshi-aki
Quantum Physics
Solving large-scale linear systems problems is a cornerstone in scientific and industrial computing. Classical iterative solvers face increasing difficulty as the number of unknowns becomes large, while fully quantum linear solvers require fault-tolerant resources that remain far beyond near-term feasibility. Here we propose a quantum-accelerated conjugate gradient (QACG) method in which a fault-tolerant quantum algorithm is used exclusively to construct a spectrally informed initial guess for a classical conjugate gradient (CG) solver. We estimate the total runtime and resource requirements of an integrated quantum-HPC platform for the 3D Poisson equation. A central feature of QACG is the controllable decomposition of the condition number between the quantum and the classical solver, enabling flexible allocation of computational effort. Under explicit architectural assumptions, we identify regimes in which QACG yields a runtime advantage over purely classical approaches while requiring substantially fewer quantum resources than end-to-end quantum linear solvers. These results illustrate a concrete pathway toward the scientific and industrial use of early-stage fault-tolerant quantum computing and point to a integrated paradigm in which quantum devices act as accelerators within high-performance computing workflows.
title Quantum-accelerated conjugate gradient method via spectral initialization
topic Quantum Physics
url https://arxiv.org/abs/2602.09696