Magnetic-field-dependent trap loss of ultracold metastable helium

Abstract

We have experimentally studied the magnetic-field dependence of the decay of a Bose-Einstein condensate of metastable 4He atoms confined in an optical dipole trap, for atoms in the m=+1 and m=-1 magnetic substates, and up to 450 G. Our measurements confirm longstanding calculations of the two-body loss rate coefficient that show an increase above 50 G. We demonstrate that for m=-1 atoms decay is due to three-body recombination only, with a three-body loss rate coefficient of 6.5( 0.4)stat( 0.6)sys×10 -27 cm6s -1, which is interesting in the context of universal few-body theory. We have also searched for a recently predicted d-wave Feshbach resonance, but did not observe it. © 2012 American Physical Society.