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Main Authors: Petersson, N. Anders, Hodges-Heilmann, Chase, Günther, Stefanie
Format: Preprint
Published: 2026
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Online Access:https://arxiv.org/abs/2603.13990
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author Petersson, N. Anders
Hodges-Heilmann, Chase
Günther, Stefanie
author_facet Petersson, N. Anders
Hodges-Heilmann, Chase
Günther, Stefanie
contents We study low-rank tensor methods for the numerical solution of Schrödinger's equation with time-independent and explicitly time-dependent Hamiltonians, motivated by large-scale simulations of many-body quantum systems and quantum computing devices subject to time-dependent control pulses. We outline the recent application of the "basis update and Galerkin" (BUG) method for tensor trains, and describe the established TDVP and TDVP-2 algorithms based on the time-dependent variational principle. For comparison, we also consider the BUG method in the Tucker format. All these approaches enable memory efficient representations of partially entangled quantum states and thereby mitigate the exponential cost of conventional state-vector formulations. The rank-adaptivity relies on the truncated singular value decomposition, in which the rank of a matrix is reduced by setting its smallest singular values to zero, based on a threshold parameter that controls the truncation error. Numerical experiments on representative time-independent and time-dependent Hamiltonian models quantify the tradeoff between accuracy and compression across methods, with particular attention to the interplay between the time-step and the truncation threshold, and how the computational effort scales with the number of sub-systems in the quantum system.
format Preprint
id arxiv_https___arxiv_org_abs_2603_13990
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Dynamical Simulations of Schrödinger's Equation via Rank-Adaptive Tensor Decompositions
Petersson, N. Anders
Hodges-Heilmann, Chase
Günther, Stefanie
Quantum Physics
Mathematical Physics
We study low-rank tensor methods for the numerical solution of Schrödinger's equation with time-independent and explicitly time-dependent Hamiltonians, motivated by large-scale simulations of many-body quantum systems and quantum computing devices subject to time-dependent control pulses. We outline the recent application of the "basis update and Galerkin" (BUG) method for tensor trains, and describe the established TDVP and TDVP-2 algorithms based on the time-dependent variational principle. For comparison, we also consider the BUG method in the Tucker format. All these approaches enable memory efficient representations of partially entangled quantum states and thereby mitigate the exponential cost of conventional state-vector formulations. The rank-adaptivity relies on the truncated singular value decomposition, in which the rank of a matrix is reduced by setting its smallest singular values to zero, based on a threshold parameter that controls the truncation error. Numerical experiments on representative time-independent and time-dependent Hamiltonian models quantify the tradeoff between accuracy and compression across methods, with particular attention to the interplay between the time-step and the truncation threshold, and how the computational effort scales with the number of sub-systems in the quantum system.
title Dynamical Simulations of Schrödinger's Equation via Rank-Adaptive Tensor Decompositions
topic Quantum Physics
Mathematical Physics
url https://arxiv.org/abs/2603.13990