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Main Authors: Köcher, Nikolas, Rose, Hendrik, Bharadwaj, Sachin S., Schumacher, Jörg, Schumacher, Stefan
Format: Preprint
Published: 2024
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Online Access:https://arxiv.org/abs/2407.02989
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author Köcher, Nikolas
Rose, Hendrik
Bharadwaj, Sachin S.
Schumacher, Jörg
Schumacher, Stefan
author_facet Köcher, Nikolas
Rose, Hendrik
Bharadwaj, Sachin S.
Schumacher, Jörg
Schumacher, Stefan
contents The time-dependent one-dimensional nonlinear Schrödinger equation (NLSE) is solved numerically by a hybrid pseudospectral-variational quantum algorithm that connects a pseudospectral step for the Hamiltonian term with a variational step for the nonlinear term. The Hamiltonian term is treated as an integrating factor by forward and backward Fourier transformations, which are here carried out classically. This split allows us to avoid higher-order time integration schemes, to apply a first-order explicit time stepping for the remaining nonlinear NLSE term in a variational algorithm block, and thus to avoid numerical instabilities. We demonstrate that the analytical solution is reproduced with a small root mean square error for a long time interval over which a nonlinear soliton propagates significantly forward in space while keeping its shape. We analyze the accuracy of the quantum algorithm and compare it with classical approaches. Furthermore, we investigate the influence of algorithm parameters on the accuracy of the results, including the temporal step width and the depth of the quantum circuit.
format Preprint
id arxiv_https___arxiv_org_abs_2407_02989
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Numerical solution of nonlinear Schrödinger equation by a hybrid pseudospectral-variational quantum algorithm
Köcher, Nikolas
Rose, Hendrik
Bharadwaj, Sachin S.
Schumacher, Jörg
Schumacher, Stefan
Quantum Physics
The time-dependent one-dimensional nonlinear Schrödinger equation (NLSE) is solved numerically by a hybrid pseudospectral-variational quantum algorithm that connects a pseudospectral step for the Hamiltonian term with a variational step for the nonlinear term. The Hamiltonian term is treated as an integrating factor by forward and backward Fourier transformations, which are here carried out classically. This split allows us to avoid higher-order time integration schemes, to apply a first-order explicit time stepping for the remaining nonlinear NLSE term in a variational algorithm block, and thus to avoid numerical instabilities. We demonstrate that the analytical solution is reproduced with a small root mean square error for a long time interval over which a nonlinear soliton propagates significantly forward in space while keeping its shape. We analyze the accuracy of the quantum algorithm and compare it with classical approaches. Furthermore, we investigate the influence of algorithm parameters on the accuracy of the results, including the temporal step width and the depth of the quantum circuit.
title Numerical solution of nonlinear Schrödinger equation by a hybrid pseudospectral-variational quantum algorithm
topic Quantum Physics
url https://arxiv.org/abs/2407.02989