2013/07/11 by Richard J. Fletcher, Alexander L. Gaunt, Nir Navon +2 · 2 citations
Physics and Astronomy · #cond-mat.quant-gas #physics.atom-ph #quant-ph
paper · pdf · doi:10.1103/physrevlett.111.125303
published as Phys. Rev. Lett. 111, 125303 (2013) · 4 pages, 5 figures
arxiv created 2013/07/11 · arxiv updated 2013/09/24
We study the stability of a thermal 39K Bose gas across a broad Feshbach resonance, focusing on the unitary regime, where the scattering length a exceeds the thermal wavelength λ. We measure the general scaling laws relating the particle-loss and heating rates to the temperature, scattering length, and atom number. Both at unitarity and for positive a ≪ λ we find agreement with three-body theory. However, for a<0 and away from unitarity, we observe significant four-body decay. At unitarity, the three-body loss coefficient, L3 ∝ λ4, is three times lower than the universal theoretical upper bound. This reduction is a consequence of species-specific Efimov physics and makes 39K particularly promising for studies of many-body physics in a unitary Bose gas.