Ground and excited-state energies with analytic errors and short time evolution on a quantum computer

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Main Authors: Stroschein, Timothy, Castaldo, Davide, Reiher, Markus
Format: Preprint
Published: 2025
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author Stroschein, Timothy
Castaldo, Davide
Reiher, Markus
author_facet Stroschein, Timothy
Castaldo, Davide
Reiher, Markus
contents Accurately solving the Schrödinger equation remains a central challenge in computational physics, chemistry, and materials science. Here, we propose an alternative eigenvalue problem based on a system's autocorrelation function, avoiding direct reference to a wave function. In particular, we develop a rigorous approximation framework that enables precise frequency estimation from a finite number of signal samples. Our analysis builds on new results involving prolate spheroidal wave functions and yields error bounds that reveal a sharp accuracy transition governed by the observation time and spectral density of the signal. These results are very general and thus carry far. As one important example application we consider the quantum computation for molecular systems. By combining our spectral method with a quantum subroutine for signal generation, we define quantum prolate diagonalization (QPD) - a hybrid classical-quantum algorithm. QPD simultaneously estimates ground and excited state energies within chemical accuracy at the Heisenberg limit. An analysis of different input states demonstrates the robustness of the method, showing that high precision can be retained even under imperfect state preparation.
format Preprint
id arxiv_https___arxiv_org_abs_2507_15148
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Ground and excited-state energies with analytic errors and short time evolution on a quantum computer
Stroschein, Timothy
Castaldo, Davide
Reiher, Markus
Quantum Physics
Mathematical Physics
Chemical Physics
Computational Physics
Accurately solving the Schrödinger equation remains a central challenge in computational physics, chemistry, and materials science. Here, we propose an alternative eigenvalue problem based on a system's autocorrelation function, avoiding direct reference to a wave function. In particular, we develop a rigorous approximation framework that enables precise frequency estimation from a finite number of signal samples. Our analysis builds on new results involving prolate spheroidal wave functions and yields error bounds that reveal a sharp accuracy transition governed by the observation time and spectral density of the signal. These results are very general and thus carry far. As one important example application we consider the quantum computation for molecular systems. By combining our spectral method with a quantum subroutine for signal generation, we define quantum prolate diagonalization (QPD) - a hybrid classical-quantum algorithm. QPD simultaneously estimates ground and excited state energies within chemical accuracy at the Heisenberg limit. An analysis of different input states demonstrates the robustness of the method, showing that high precision can be retained even under imperfect state preparation.
title Ground and excited-state energies with analytic errors and short time evolution on a quantum computer
topic Quantum Physics
Mathematical Physics
Chemical Physics
Computational Physics
url https://arxiv.org/abs/2507.15148