High-precision quantum algorithms for partial differential equations

Autor: Andrew M. Childs, Jin-Peng Liu, Aaron Ostrander
Jazyk: angličtina
Rok vydání: 2021
Předmět:
Zdroj: Quantum, Vol 5, p 574 (2021)
Druh dokumentu: article
ISSN: 2521-327X
DOI: 10.22331/q-2021-11-10-574
Popis: Quantum computers can produce a quantum encoding of the solution of a system of differential equations exponentially faster than a classical algorithm can produce an explicit description. However, while high-precision quantum algorithms for linear ordinary differential equations are well established, the best previous quantum algorithms for linear partial differential equations (PDEs) have complexity $\mathrm{poly}(1/\epsilon)$, where $\epsilon$ is the error tolerance. By developing quantum algorithms based on adaptive-order finite difference methods and spectral methods, we improve the complexity of quantum algorithms for linear PDEs to be $\mathrm{poly}(d, \log(1/\epsilon))$, where $d$ is the spatial dimension. Our algorithms apply high-precision quantum linear system algorithms to systems whose condition numbers and approximation errors we bound. We develop a finite difference algorithm for the Poisson equation and a spectral algorithm for more general second-order elliptic equations.
Databáze: Directory of Open Access Journals