Floquet engineering of competing antiferromagnetism and $d$-wave superconductivity on the square lattice
Year: 2026
Type: preprint
Abstract: We propose a driven Lieb--Hubbard quantum simulator whose prethermal dynamics realize a square-lattice spin-1/2 fermion model with independently tunable repulsive on-site and attractive bond interactions. Periodically modulating the charge-transfer offset between the site ($d$) and bond ($p$) orbitals of the Lieb lattice brings a $p$-orbital doublon energetically close to a pair in the $d$ manifold while keeping all $p$-orbital singlons off resonance, thereby creating a synthetic ``negative-$U$'' center on a Lieb-lattice bond site. Two controlled eliminations then generate a compact bond attraction in the reduced $d$-only model on the square lattice, despite the microscopic repulsion in the $p$ orbital. The resulting interaction $J$ is tunable independently of the Hubbard repulsion $U_d$ on the $d$ orbitals, while interference between photon-assisted paths provides access to an intermediate-coupling regime in which $J$ and $U_d$ are both comparable to the effective hopping. At half filling, a mean-field calculation in this regime finds adjacent antiferromagnetic and $d$-wave superconducting phases, as well as narrow coexistence regions, suggesting close competition between these orders. We discuss the branch-preparation, prethermal, and higher-band conditions required to translate the formal construction into an optical-lattice protocol. More broadly, our work identifies a structural similarity between Floquet systems and electron-phonon problems that may guide the design of novel quantum-simulation protocols.
Source: arXiv (Cornell University)
Authors: Han, Zhaoyu, Sachdev, Subir
Institution: Harvard University
Language: English
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7204941567