Trotter simulation of vibrational Hamiltonians on a quantum computer

Fuente: arXiv
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Main Authors: Malpathak, Shreyas, Kallullathil, Sangeeth Das, Loaiza, Ignacio, Fomichev, Stepan, Arrazola, Juan Miguel, Izmaylov, Artur F.
Format: Preprint
Published: 2025
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author Malpathak, Shreyas
Kallullathil, Sangeeth Das
Loaiza, Ignacio
Fomichev, Stepan
Arrazola, Juan Miguel
Izmaylov, Artur F.
author_facet Malpathak, Shreyas
Kallullathil, Sangeeth Das
Loaiza, Ignacio
Fomichev, Stepan
Arrazola, Juan Miguel
Izmaylov, Artur F.
contents Simulating vibrational dynamics is essential for understanding molecular structure, unlocking useful applications such as vibrational spectroscopy for high-fidelity chemical detection. Quantum algorithms for vibrational dynamics are emerging as a promising alternative to resource-demanding classical approaches, but this domain is largely underdeveloped compared to quantum simulations of electronic structure. In this work, we describe in detail three distinct forms of the vibrational Hamiltonian: canonical bosonic quantization, real space representation, and the Christiansen second-quantized form. Leveraging Lie algebraic properties of each, we develop efficient fragmentation schemes to enable the use of Trotter product formulas for simulating time evolution. We introduce circuits required to implement time evolution in each form, and highlight factors that contribute to the simulation cost, including the choice of vibrational coordinates. Using a perturbative approach for the Trotter error, we obtain tight estimates of T gate cost for the simulation of time evolution in each form, enabling their quantitative comparison. Combining tight Trotter error estimates and efficient fragmentation schemes, we find that for the medium-sized CH$_4$ molecule with 9 vibrational modes, time evolution for approximately 1.8 ps may be simulated using as little as 36 qubits and approximately $3 \times 10^{8}$ T gates -- an order-of-magnitude speedup over prior-art algorithms. Finally, we present calculations of vibrational spectra using each form to demonstrate the fidelity of our algorithms. This work presents a unified and highly optimized framework that makes simulating vibrational dynamics an attractive use case for quantum computers.
format Preprint
id arxiv_https___arxiv_org_abs_2508_11865
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Trotter simulation of vibrational Hamiltonians on a quantum computer
Malpathak, Shreyas
Kallullathil, Sangeeth Das
Loaiza, Ignacio
Fomichev, Stepan
Arrazola, Juan Miguel
Izmaylov, Artur F.
Quantum Physics
Chemical Physics
Simulating vibrational dynamics is essential for understanding molecular structure, unlocking useful applications such as vibrational spectroscopy for high-fidelity chemical detection. Quantum algorithms for vibrational dynamics are emerging as a promising alternative to resource-demanding classical approaches, but this domain is largely underdeveloped compared to quantum simulations of electronic structure. In this work, we describe in detail three distinct forms of the vibrational Hamiltonian: canonical bosonic quantization, real space representation, and the Christiansen second-quantized form. Leveraging Lie algebraic properties of each, we develop efficient fragmentation schemes to enable the use of Trotter product formulas for simulating time evolution. We introduce circuits required to implement time evolution in each form, and highlight factors that contribute to the simulation cost, including the choice of vibrational coordinates. Using a perturbative approach for the Trotter error, we obtain tight estimates of T gate cost for the simulation of time evolution in each form, enabling their quantitative comparison. Combining tight Trotter error estimates and efficient fragmentation schemes, we find that for the medium-sized CH$_4$ molecule with 9 vibrational modes, time evolution for approximately 1.8 ps may be simulated using as little as 36 qubits and approximately $3 \times 10^{8}$ T gates -- an order-of-magnitude speedup over prior-art algorithms. Finally, we present calculations of vibrational spectra using each form to demonstrate the fidelity of our algorithms. This work presents a unified and highly optimized framework that makes simulating vibrational dynamics an attractive use case for quantum computers.
title Trotter simulation of vibrational Hamiltonians on a quantum computer
topic Quantum Physics
Chemical Physics
url https://arxiv.org/abs/2508.11865