Collisional shielding of a bosonic gas of polar molecules*

Degenerate gases of bosonic polar molecules are expected to possess a rich set of many-body phases enabled by their long-range dipolar interactions. However, evaporative cooling of these molecules to degeneracy has so far been hindered by rapid collisional losses in the bulk. Building off recent theoretical and experimental advances in the shielding of fermionic molecules with static electric fields, we demonstrate collisional shielding of bosonic NaRb molecules by using eight in-vacuum electrodes to generate a uniform electric field of 4.5 kV/cm. This field lies just above a resonance between two pairs of rotational states, resulting in a strongly repulsive collisional barrier at short-range. Here, we observe molecular lifetimes of several seconds in a bulk trap, consistent with one-body loss. Combined with the molecules' fast thermalization rate due to their –0.4 D dipole moment at the shielding electric field, this long lifetime presents a clear pathway to achieving a high phase space density Bose gas of NaRb through evaporative cooling. Moreover, by loading this gas into a 2D lattice, we hope to use our recently constructed molecular quantum gas microscope to probe the dipolar Bose-Hubbard model with single-site resolution.