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Bibliographic Details
Main Authors: Feng, Xiaoning, Nejad, Arman, Tew, David P.
Format: Preprint
Published: 2026
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Online Access:https://arxiv.org/abs/2603.21122
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author Feng, Xiaoning
Nejad, Arman
Tew, David P.
author_facet Feng, Xiaoning
Nejad, Arman
Tew, David P.
contents We develop a time-dependent, grid-based framework for simulating infrared spectra that is specifically designed for quantum computers. The proposed circuit employs a probabilistic strategy for applying the non-unitary dipole operator and an Split Operator-Quantum Fourier Transform time evolution scheme. Using a vibrational model of the water molecule as a test system, our classical emulation results demonstrate accurate determination of fundamental and overtone band positions and intensities via Fourier-transformed dipole-dipole autocorrelation functions. We also identify the optimal time parameters that minimise gate depths while maintaining high fidelity. For further resource reduction, we validate the feasibility of utilising harmonic oscillator approximations in state preparation and dipole operator truncations. With its scalability to higher-dimensional normal mode spaces, this wavefunction-based approach establishes a robust foundation for studying IR spectra on future quantum hardware.
format Preprint
id arxiv_https___arxiv_org_abs_2603_21122
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle A Grid-Based Quantum Algorithm for the Time-Dependent Simulation of Infrared Spectra
Feng, Xiaoning
Nejad, Arman
Tew, David P.
Quantum Physics
We develop a time-dependent, grid-based framework for simulating infrared spectra that is specifically designed for quantum computers. The proposed circuit employs a probabilistic strategy for applying the non-unitary dipole operator and an Split Operator-Quantum Fourier Transform time evolution scheme. Using a vibrational model of the water molecule as a test system, our classical emulation results demonstrate accurate determination of fundamental and overtone band positions and intensities via Fourier-transformed dipole-dipole autocorrelation functions. We also identify the optimal time parameters that minimise gate depths while maintaining high fidelity. For further resource reduction, we validate the feasibility of utilising harmonic oscillator approximations in state preparation and dipole operator truncations. With its scalability to higher-dimensional normal mode spaces, this wavefunction-based approach establishes a robust foundation for studying IR spectra on future quantum hardware.
title A Grid-Based Quantum Algorithm for the Time-Dependent Simulation of Infrared Spectra
topic Quantum Physics
url https://arxiv.org/abs/2603.21122