Direct measurement of the heat capacity of a Bose-Einstein condensate

S. K. Ruddell,∗ D. H. White, A. Ullah,† and M. D. Hoogerland Department of Physics, University of Auckland, Private Bag 92019, Auckland, New Zealand

We transfer a known quantity of energy to a harmonically trapped Bose-Einstein condensate in order to study the resulting thermodynamics. We consider two methods, the first using a free expansion under gravity and the second using an optical standing wave to diffract the atoms in the potential. We investigate the effect of interactions on the resulting thermodynamics and compare our results to theory, with no adjustable parameters, providing a quantitative analysis of the heat capacity of our system.