Year: 2025
Type: preprint
Abstract: Simulations of lattice particle - phonon systems are fundamentally restricted by the exponential growth of the number of quantum states with the lattice size. Here, we demonstrate an algorithm that constructs the lowest eigenvalue and eigenvector for the Holstein model in extended lattices from eigenvalue problems for small, independent lattice segments. This leads to exponential reduction of the computational Hilbert space and allows applications of variational quantum algorithms to particle - phonon interactions in large lattices. We illustrate that the ground state of the Holstein polaron in the entire range of electron - phonon coupling, from weak to strong, and the lowest phonon frequency ($ω/t = 0.1$) considered by numerical calculations to date can be obtained from a sequence of up to four-site problems. When combined with quantum algorithms, the present approach leads to a dramatic reduction of required quantum resources. We show that the ground state of the Holstein polaron in a lattice with 100 sites and 32 site phonons can be computed by a variational quantum eigensolver with 11 qubits.
Source: arXiv (Cornell University)
Authors: Torabian, Elham, Krems, Roman V.
Institution: University of British Columbia
Language: English
Topic: Quantum many-body systems
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W4407308973