Variational Time Evolution Compression for Solving Impurity Models on Quantum Hardware

Fuente: arXiv
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Main Authors: Wolf, Stefan, Eckstein, Martin, Hartmann, Michael J.
Format: Preprint
Published: 2025
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author Wolf, Stefan
Eckstein, Martin
Hartmann, Michael J.
author_facet Wolf, Stefan
Eckstein, Martin
Hartmann, Michael J.
contents Dynamical mean-field theory (DMFT) is a useful tool to analyze models of strongly correlated fermions like the Hubbard model. In DMFT, the lattice of the model is replaced by a single impurity site embedded in an effective bath. The resulting single impurity Anderson model (SIAM) can then be solved self-consistently with a quantum-classical hybrid algorithm. This procedure involves repeatedly preparing the ground state on a quantum computer and evolving it in time to measure the Greens function. We here develop an approximation of the time evolution operator for this setting by training a Hamiltonian variational ansatz. The parameters of the ansatz are obtained via a variational quantum algorithm that utilizes a small number of time steps, given by the Suzuki-Trotter expansion of the time evolution operator, to guide the evolution of the parameters. The resulting circuit has a fixed depth for the time evolution depending on the size of the bath and is significantly shallower than a comparable Suzuki-Trotter expansion.
format Preprint
id arxiv_https___arxiv_org_abs_2508_10526
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Variational Time Evolution Compression for Solving Impurity Models on Quantum Hardware
Wolf, Stefan
Eckstein, Martin
Hartmann, Michael J.
Quantum Physics
Strongly Correlated Electrons
Dynamical mean-field theory (DMFT) is a useful tool to analyze models of strongly correlated fermions like the Hubbard model. In DMFT, the lattice of the model is replaced by a single impurity site embedded in an effective bath. The resulting single impurity Anderson model (SIAM) can then be solved self-consistently with a quantum-classical hybrid algorithm. This procedure involves repeatedly preparing the ground state on a quantum computer and evolving it in time to measure the Greens function. We here develop an approximation of the time evolution operator for this setting by training a Hamiltonian variational ansatz. The parameters of the ansatz are obtained via a variational quantum algorithm that utilizes a small number of time steps, given by the Suzuki-Trotter expansion of the time evolution operator, to guide the evolution of the parameters. The resulting circuit has a fixed depth for the time evolution depending on the size of the bath and is significantly shallower than a comparable Suzuki-Trotter expansion.
title Variational Time Evolution Compression for Solving Impurity Models on Quantum Hardware
topic Quantum Physics
Strongly Correlated Electrons
url https://arxiv.org/abs/2508.10526