Large Trimers from Three-Body Interactions in One-Dimensional Lattices

Few-body bound states have been extensively explored in cold atomic gases with a desire to realize large molecular complexes. Here, we investigate the formation of trimers in an infinite one-dimensional lattice with hard-core two- and three-body interactions of relevance to Rydberg atoms and polar molecules in optical lattices, and other physical systems such as the fractional Hall states. We determine the stability regions for attractively and repulsively bound trimers. We discover a regime of large spatially extended trimers that are stabilized by the interplay of attractive two-body, $U$ , and repulsive three-body, $V$ , interactions and persist despite extremely large $V$. These bound states present a new direction in the search for large few-body complexes in cold atoms.