عنوان

Quantum Algorithms for Differential Equations

شماره

TL52285

زبان متن نوشتاري يا گفتاري و مانند آن

انگلیسی

عنوان اصلي

Quantum Algorithms for Differential Equations

نام عام مواد

[Thesis]

نام نخستين پديدآور

Ostrander, Aaron Jacob

نام ساير پديدآوران

Childs, Andrew

نام ناشر، پخش کننده و غيره

University of Maryland, College Park

تاریخ نشرو بخش و غیره

2019

متن يادداشت

108 p.

جزئيات پايان نامه و نوع درجه آن

Ph.D.

کسي که مدرک را اعطا کرده

University of Maryland, College Park

امتياز متن

2019

متن يادداشت

This thesis describes quantum algorithms for Hamiltonian simulation, ordinary differential equations (ODEs), and partial differential equations (PDEs). Product formulas are used to simulate Hamiltonians which can be expressed as a sum of terms which can each be simulated individually. By simulating each of these terms in sequence, the net effect approximately simulates the total Hamiltonian. We find that the error of product formulas can be improved by randomizing over the order in which the Hamiltonian terms are simulated. We prove that this approach is asymptotically better than ordinary product formulas and present numerical comparisons for small numbers of qubits. The ODE algorithm applies to the initial value problem for time-independent first order linear ODEs. We approximate the propagator of the ODE by a truncated Taylor series, and we encode the initial value problem in a large linear system. We solve this linear system with a quantum linear system algorithm (QLSA) whose output we perform a post-selective measurement on. The resulting state encodes the solution to the initial value problem. We prove that our algorithm is asymptotically optimal with respect to several system parameters. The PDE algorithms apply the finite difference method (FDM) to Poisson's equation, the wave equation, and the Klein-Gordon equation. We use high order FDM approximations of the Laplacian operator to develop linear systems for Poisson's equation in cubic volumes under periodic, Neumann, and Dirichlet boundary conditions. Using QLSAs, we output states encoding solutions to Poisson's equation. We prove that our algorithm is exponentially faster with respect to the spatial dimension than analogous classical algorithms. We also consider how high order Laplacian approximations can be used for simulating the wave and Klein-Gordon equations. We consider under what conditions it suffices to use Hamiltonian simulation for time evolution, and we propose an algorithm for these cases that uses QLSAs for state preparation and post-processing.

اصطلاح موضوعی

Computer science

اصطلاح موضوعی

Quantum physics

مستند نام اشخاص تاييد نشده

Ostrander, Aaron Jacob

مستند نام اشخاص تاييد نشده

Childs, Andrew

مستند نام تنالگان تاييد نشده

University of Maryland, College Park

نام الکترونيکي

فرمت انتشار

p

نوع ماده

[Thesis]

کد کاربرگه

276903

سطح دسترسي

a

تكميل شده

Y