Adaptive quantum dynamics with the time-dependent variational Monte Carlo method

Fuente: arXiv
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Autori principali: Salioni, Raffaele, Martinazzo, Rocco, Galli, Davide Emilio, Apostoli, Christian
Natura: Preprint
Pubblicazione: 2025
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author Salioni, Raffaele
Martinazzo, Rocco
Galli, Davide Emilio
Apostoli, Christian
author_facet Salioni, Raffaele
Martinazzo, Rocco
Galli, Davide Emilio
Apostoli, Christian
contents We introduce an extension of the time-dependent variational Monte Carlo (tVMC) method that adaptively controls the expressivity of the variational quantum state during the simulation of the dynamics. This adaptive tVMC (atVMC) approach is specifically designed to enhance numerical stability when overparameterized variational ansätze lead to ill-conditioned equations of motion. Building on the concept of the local-in-time error (LITE), a measure of the deviation between variational and exact evolution, we introduce a procedure to quantify each parameter's contribution to reducing the LITE, using only quantities already computed in standard tVMC simulations. These relevance estimates guide the selective evolution of only the most significant parameters at each time step, while maintaining a prescribed level of accuracy. We benchmark the algorithm on quantum quenches in the one-dimensional transverse-field Ising model using both spin-Jastrow and restricted Boltzmann machine wave functions, with an emphasis on overparameterized regimes. The adaptive scheme significantly improves numerical stability and reduces the need for strong regularization, enabling reliable simulations with highly expressive variational ansätze.
format Preprint
id arxiv_https___arxiv_org_abs_2506_08575
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Adaptive quantum dynamics with the time-dependent variational Monte Carlo method
Salioni, Raffaele
Martinazzo, Rocco
Galli, Davide Emilio
Apostoli, Christian
Quantum Physics
Other Condensed Matter
Statistical Mechanics
Computational Physics
We introduce an extension of the time-dependent variational Monte Carlo (tVMC) method that adaptively controls the expressivity of the variational quantum state during the simulation of the dynamics. This adaptive tVMC (atVMC) approach is specifically designed to enhance numerical stability when overparameterized variational ansätze lead to ill-conditioned equations of motion. Building on the concept of the local-in-time error (LITE), a measure of the deviation between variational and exact evolution, we introduce a procedure to quantify each parameter's contribution to reducing the LITE, using only quantities already computed in standard tVMC simulations. These relevance estimates guide the selective evolution of only the most significant parameters at each time step, while maintaining a prescribed level of accuracy. We benchmark the algorithm on quantum quenches in the one-dimensional transverse-field Ising model using both spin-Jastrow and restricted Boltzmann machine wave functions, with an emphasis on overparameterized regimes. The adaptive scheme significantly improves numerical stability and reduces the need for strong regularization, enabling reliable simulations with highly expressive variational ansätze.
title Adaptive quantum dynamics with the time-dependent variational Monte Carlo method
topic Quantum Physics
Other Condensed Matter
Statistical Mechanics
Computational Physics
url https://arxiv.org/abs/2506.08575