Competing instabilities of cold atoms on self-assembled dipolar lattices

Ahmet Keleş, Erhai Zhao

Wei-Lin Tu, Huan-Kuang Wu, Takafumi Suzuki +2 more

Barnali Chakrabarti, N. D. Chavda, Andrea Trombettoni +1 more

Guido Pupillo, Andreas Griessner, Andrea Micheli +3 more

We study the realization of lattice models, where cold atoms and molecules move as extra particles in a dipolar crystal of trapped polar molecules. The crystal is a self-assembled floating mesoscopic lattice structure with quantum dynamics given by phonons. We show that within an experimentally accessible parameter regime extended Hubbard models with tunable long-range phonon-mediated interactions describe the effective dynamics of dressed particles.

Guido Masella, Adriano Angelone, Fabio Mezzacapo +2 more

Strong, long-range interactions present a unique challenge for the theoretical investigation of quantum many-body lattice models, due to the generation of large numbers of competing states at low energy. Here, we investigate a class of extended bosonic Hubbard models with off-site terms interpolating between short and infinite range, thus allowing for an exact numerical solution for all interaction strengths. We predict a novel type of stripe crystal at strong coupling. Most interestingly, for intermediate interaction strengths we demonstrate that the stripes can turn superfluid, thus leading to a self-assembled array of quasi-one-dimensional superfluids. These bosonic superstripes turn into an isotropic supersolid with decreasing the interaction strength. The mechanism for stripe formation is based on cluster self-assembling in the corresponding classical ground state, reminiscent of classical soft-matter models of polymers, different from recently proposed mechanisms for cold gases of alkali or dipolar magnetic atoms.

Daniel J. Gauthier, Joel A. Greenberg

We observe spontaneous parametric oscillation in a laser-driven cloud of cold atoms. The threshold for this instability is lowered dramatically due to self-assembled atomic gratings that allow for self-phase matching of atom-field wave mixing processes.