Realization of a bosonic antiferromagnet

Quantum antiferromagnets are of broad interest in condensed-matter physics as they provide a platform for studying exotic many-body states 1 including spin liquids 2 and high-temperature superconductors 3 . Here we report on the creation of a one-dimensional Heisenberg antiferromagnet with ultracold bosons. In a two-component Bose–Hubbard system, we switch the sign of the spin-exchange interaction and realize the isotropic antiferromagnetic Heisenberg model in an extended 70-site chain. Starting from a low-entropy Néel-ordered state, we use optimized adiabatic passage to approach the bosonic antiferromagnet. We demonstrate the establishment of antiferromagnetism by probing the evolution of staggered magnetization and spin correlations of the system. Compared with condensed-matter systems, ultracold gases in optical lattices can be microscopically engineered and measured, offering remarkable advantages for exploring bosonic magnetism and spin dynamics 4 .