The superfluid fountain effect in a Bose-Einstein condensate

TL;DR

This paper theoretically demonstrates the superfluid fountain effect in a Bose-Einstein condensate setup, showing superfluid flow from cold to hot regions while the normal component remains blocked.

Contribution

It introduces a simple experimental setup to observe the superfluid fountain effect in BECs and analyzes the superfluid and normal components of the flow.

Findings

Superfluid component flows from cold to hot vessel.

Normal component is blocked in the hot vessel.

The effect can be observed using classical field approximation.

Abstract

We consider a simple experimental setup, based on a harmonic confinement, where a Bose-Einstein condensate and a thermal cloud of weakly interacting alkali atoms are trapped in two different vessels connected by a narrow channel. Using the classical field approximation, as described in J. Phys. B 40, R1 (2007) and optimized in Phys. Rev. A 81, 013629 (2010) for an arbitrary trapping potential, we theoretically investigate the analog of the celebrated superfluid helium fountain effect. We show that this thermo-mechanical effect might indeed be observed in this system. By analyzing the dynamics of the system, we are able to identify the superfluid and normal components of the flow as well as to distinguish the condensate fraction from the superfluid component. We show that the superfluid component can easily flow from the colder vessel to the hotter one while the normal component is practically blocked in the latter.