Tailoring tensor network techniques to the quantics representation for highly inhomogeneous problems and few body problems

Fuente: arXiv
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Main Authors: Li, Jheng-Wei, Jolly, Nicolas, Waintal, Xavier
Format: Preprint
Published: 2026
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author Li, Jheng-Wei
Jolly, Nicolas
Waintal, Xavier
author_facet Li, Jheng-Wei
Jolly, Nicolas
Waintal, Xavier
contents Tensor network techniques are becoming increasingly popular tools to solve partial differential equations within the so-called quantics representation. Their popularity stems from the fact that their spatial resolution depends only logarithmically on the number of grid points, making them very tempting approaches in situations where two or more characteristic length scales are vastly different. A first generation of technique used ``out-of-the-box'' algorithms of the tensor network toolkit (e.g. the celebrated Density Matrix Product State (DMRG) algorithm) to solve these problems. These techniques were designed for situations (e.g. quantum magnetism) where the different degrees of freedom (e.g. spins) play equivalent roles. In the quantics representation, however, the different degrees of freedom correspond to the physics at different scales and therefore play inequivalent role. Here we show that by tailoring the tensor network algorithms to this particular case, in the spirit of the multigrid approach, we obtain faster and more robust convergence of the algorithms. We showcase the approach on linear (Poisson equation) and eigenvalue (Schrödinger equation) problems in two, three and four dimensions. Our simulations involve up to $2^{80}$ grid points and would represent, we argue, a very strong challenge for conventional approaches.
format Preprint
id arxiv_https___arxiv_org_abs_2604_09337
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Tailoring tensor network techniques to the quantics representation for highly inhomogeneous problems and few body problems
Li, Jheng-Wei
Jolly, Nicolas
Waintal, Xavier
Quantum Physics
Tensor network techniques are becoming increasingly popular tools to solve partial differential equations within the so-called quantics representation. Their popularity stems from the fact that their spatial resolution depends only logarithmically on the number of grid points, making them very tempting approaches in situations where two or more characteristic length scales are vastly different. A first generation of technique used ``out-of-the-box'' algorithms of the tensor network toolkit (e.g. the celebrated Density Matrix Product State (DMRG) algorithm) to solve these problems. These techniques were designed for situations (e.g. quantum magnetism) where the different degrees of freedom (e.g. spins) play equivalent roles. In the quantics representation, however, the different degrees of freedom correspond to the physics at different scales and therefore play inequivalent role. Here we show that by tailoring the tensor network algorithms to this particular case, in the spirit of the multigrid approach, we obtain faster and more robust convergence of the algorithms. We showcase the approach on linear (Poisson equation) and eigenvalue (Schrödinger equation) problems in two, three and four dimensions. Our simulations involve up to $2^{80}$ grid points and would represent, we argue, a very strong challenge for conventional approaches.
title Tailoring tensor network techniques to the quantics representation for highly inhomogeneous problems and few body problems
topic Quantum Physics
url https://arxiv.org/abs/2604.09337