Microscopic theory of the Hubbard interaction in low-dimensional optical lattices

Fuente: arXiv
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Auteurs principaux: Adlong, Haydn S., Levinsen, Jesper, Parish, Meera M.
Format: Preprint
Publié: 2024
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author Adlong, Haydn S.
Levinsen, Jesper
Parish, Meera M.
author_facet Adlong, Haydn S.
Levinsen, Jesper
Parish, Meera M.
contents The Hubbard model is a paradigmatic model of strongly correlated quantum matter, thus making it desirable to investigate with quantum simulators such as ultracold atomic gases. Here, we consider the problem of two atoms interacting in a quasi-one- or quasi-two-dimensional optical lattice, geometries which are routinely realized in quantum-gas-microscope experiments. We perform an exact calculation of the low-energy scattering amplitude which accounts for the effects of the transverse confinement as well as all higher Bloch bands. This goes beyond standard perturbative treatments and allows us to precisely determine the effective Hubbard on-site interaction for arbitrary $s$-wave scattering length (see source code available at [1]). In particular, we find that the Hubbard on-site interaction displays lattice-induced resonances for scattering lengths on the order of the lattice spacing, which are well within reach of current experiments. Furthermore, we show that our results are in excellent agreement with spectroscopic measurements of the Hubbard interaction for a quasi-two-dimensional square optical lattice in a quantum gas microscope. Our formalism is very general and may be extended to multi-band models and other atom-like scenarios in lattice geometries, such as exciton-exciton and exciton-electron scattering in moiré superlattices.
format Preprint
id arxiv_https___arxiv_org_abs_2409_12908
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Microscopic theory of the Hubbard interaction in low-dimensional optical lattices
Adlong, Haydn S.
Levinsen, Jesper
Parish, Meera M.
Quantum Gases
The Hubbard model is a paradigmatic model of strongly correlated quantum matter, thus making it desirable to investigate with quantum simulators such as ultracold atomic gases. Here, we consider the problem of two atoms interacting in a quasi-one- or quasi-two-dimensional optical lattice, geometries which are routinely realized in quantum-gas-microscope experiments. We perform an exact calculation of the low-energy scattering amplitude which accounts for the effects of the transverse confinement as well as all higher Bloch bands. This goes beyond standard perturbative treatments and allows us to precisely determine the effective Hubbard on-site interaction for arbitrary $s$-wave scattering length (see source code available at [1]). In particular, we find that the Hubbard on-site interaction displays lattice-induced resonances for scattering lengths on the order of the lattice spacing, which are well within reach of current experiments. Furthermore, we show that our results are in excellent agreement with spectroscopic measurements of the Hubbard interaction for a quasi-two-dimensional square optical lattice in a quantum gas microscope. Our formalism is very general and may be extended to multi-band models and other atom-like scenarios in lattice geometries, such as exciton-exciton and exciton-electron scattering in moiré superlattices.
title Microscopic theory of the Hubbard interaction in low-dimensional optical lattices
topic Quantum Gases
url https://arxiv.org/abs/2409.12908