Ultracold gas of a triel atom

Ultracold gases of triel elements (Group 13) provide a new frontier for quantum matter experiments, occupying an unexplored regime of angular momentum and magnetic interaction strength that naturally supports short-range anisotropic scattering and the potential for topological spinor physics. The triel atom indium is particularly promising, for it combines magnetic Feshbach resonances, an ultranarrow clock transition, and anisotropic light–matter interactions within a single platform. In the quantum degenerate regime, indium is expected to realize a condensate governed by an elastic, anisotropic Gross–Pitaevskii equation, which gives rise to novel quantum phases and rich dynamics.

Motivated by this prospect, we have realized an ultracold gas of indium at the ~10μK level using polarization-gradient cooling, hyperfine spin polarization, and optical lattice confinement. We also we present progress toward narrow-line cooling on the 284 nm intercombination transition (5 ²P_3/2 → 5 ⁴P_5/2), which has a natural linewidth of 20 kHz and a Doppler limit of a few μK. Reaching this regime will enable direct studies of indium’s anisotropic contact interaction, the mapping of magnetic Feshbach resonances, and ultimately the first quantum-degenerate gas of a triel element.