“…A basic aspect of Bose-Einstein condensation is the actual order of the transition. In the non-interacting case it is third order (within the Ehrenfest classification), On the other hand, order-parameter based studies of dilute Bose systems [8,9,10,11,12,13,14,15,16] as well as related effective low-energy bosonic models for underlying Fermi systems [6,17,18,19] typically truncate the effective action at quartic order biasing the system towards a second-order transition. It is however well known that different fluctuation-related effects tend to change the order of both thermal and quantum phase transitions [5,20,21,22,23,24,25,26,27,28], and often destabilize them towards first-order.…”