Optical superlattice for engineering Hubbard couplings in quantum simulation

TL;DR

This paper demonstrates how optical superlattices can precisely control tunneling, tilt, and spin couplings in ultracold fermionic gases, enabling advanced quantum simulations of Hubbard models with high tunability.

Contribution

The work introduces a phase-stable bichromatic optical superlattice that enhances control over tunneling and spin interactions in fermionic quantum gases for quantum simulation.

Findings

Achieved long-lived coherent double-well oscillations.

Demonstrated correlated quantum walks of two particles.

Engineered tunable spin couplings forming a spin ladder.

Abstract

Quantum simulations of Hubbard models with ultracold atoms rely on the exceptional control of coherent motion provided by optical lattices. Here we demonstrate enhanced tunability using an optical superlattice in a fermionic quantum gas microscope. With our phase-stable bichromatic design, we achieve a precise control of tunneling and tilt throughout the lattice, as evidenced by long-lived coherent double-well oscillations and next-nearest-neighbor quantum walks in a staggered configuration. We furthermore present correlated quantum walks of two particles initiated through a resonant pair-breaking mechanism. Finally, we engineer tunable spin couplings through local offsets and create a spin ladder with ferromagnetic and antiferromagnetic couplings along the rungs and legs, respectively. Our work underscores the high potential of optical superlattices for engineering, simulating, and detecting strongly correlated many-body quantum states.