Towards effective models for low-dimensional cuprates: From ground state Hamiltonian reconstruction to spectral functions

Hannah Lange; Tizian Blatz; Ulrich Schollwöck; Sebastian Paeckel; Annabelle Bohrdt

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arXiv · 2509.06947

Towards effective models for low-dimensional cuprates: From ground state Hamiltonian reconstruction to spectral functions

Hannah Lange·Tizian Blatz·Ulrich Schollwöck·Sebastian Paeckel·Annabelle Bohrdt

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Abstract

Understanding which minimal effective model captures the essential physics of cuprates is a key step towards unraveling the mechanism behind high-$T_c$ superconductivity. Recent measurements of the dynamical spin structure factor (DSF) in cuprate ladder compounds have indicated the presence of a large effective attraction in the single-band Hubbard model, possibly mediated by phonons. Here, we demonstrate that similar DSF features can also be captured by $t$-$J$ descriptions with or even without any attractive term. Motivated by this observation, we systematically investigate the strength and origin of different contributions to the single-band Hamiltonians by downfolding either from the three-band Emery model or the electron-phonon coupled Hubbard-Holstein model. For one-dimensional systems, we find that the extended versions of both single-band descriptions can reproduce the experimentally observed DSF signatures. Finally, we extend our analysis to two dimensions by comparing two-hole correlation functions for the different single-band models. Our results provide new insights into the long-standing question of which single-band Hamiltonian can capture the essential physics of cuprates.

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Hannah Lange, Tizian Blatz, Ulrich Schollwöck, Sebastian Paeckel, Annabelle Bohrdt. 2025-09-08. Towards effective models for low-dimensional cuprates: From ground state Hamiltonian reconstruction to spectral functions. https://arxiv.org/abs/2509.06947

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