Realization of an extremely anisotropic Heisenberg magnet in Rydberg atom arrays

TL;DR

This paper demonstrates the experimental realization of strongly anisotropic Heisenberg magnets using Rydberg atom arrays, revealing tunable magnon interactions and bound states, advancing quantum simulation of complex many-body phenomena.

Contribution

It introduces a method to control magnon interactions in Rydberg atom arrays, enabling the study of anisotropic Heisenberg models with ultrastrong coupling and bound state dynamics.

Findings

Magnon-magnon interactions can be tuned two orders of magnitude larger than hopping.

Distinct magnon bound states exhibit different dynamical behaviors.

Coherent transport of Rydberg excitations across atomic chains was achieved.

Abstract

Strong mutual interactions correlate elementary excitations of quantum matter and plays a key role in a range of emergent phenomena, from binding and condensation to quantum thermalization and many-body localization. Here, we employ a Rydberg quantum simulator to experimentally demonstrate strongly correlated spin transport in anisotropic Heisenberg magnets, where the magnon-magnon interaction can be tuned two orders of magnitude larger than the magnon hopping strength. In our approach, the motion of magnons is controlled by an induced spin-exchange interaction through Rydberg dressing, which enables coherent transport of a single Rydberg excitation across a chain of ground-state atoms. As the most prominent signature of a giant anisotropy, we show that nearby Rydberg excitations form distinct types of magnon bound states, where a tightly bound pair exhibits frozen dynamics in a fragmented Hilbert space, while a loosely bound pair propagates and establishes correlations beyond a single lattice site. Our scheme complements studies using resonant dipole-dipole interactions between Rydberg states, and opens the door to exploring quantum thermodynamics with ultrastrong interactions and kinetic constraints.