Sütő András (SZFI): Phase transitions in homogeneous systems of interacting bosons

Friday 6 Apr 2018, 14:00 → 16:00 Europe/Budapest

Immediately following the discovery of superfluidity in liquid helium, London and Tisza connected the phenomenon to Bose-Einstein condensation. Although BEC became a pillar of today`s theory, physicists have been struggling since more than half a century with a first-principle derivation of the transition in systems of interacting bosons. Here I propose such a derivation, even though my proof uses two unproved conjectures. The result assigns well-defined mathematical quantities to the fractions of normal fluid, superfluid, and condensate. In particular, it explains how superfluidity can be complete while BEC remaining partial at zero temperature.