When bosonic gases are cooled to very low temperatures, most of the atoms gather in the lowest energy state and build the so called Bose-Einstein condensate. Whereas all particles not part of the condensate behave like we expect from any gas - they flow towards colder regions, it is the condensate behavior which surprises: As a flux of absolute cold it is attracted by heat and flows towards regions of higher temperature.
A similar effect is known from superfluids and named internal convection. In our recent publication we theoretically investigate internal convection in ultracold atomic vapors and suggest that it might provide the opportunity to experimentally study heat transport on the mesoscopic scale.
