Bose condensation at high temperatures

Bose condensation is usually a low temperature phenomenon due to a low part icle number density. When the number density is kept large compared to the inverse Compton volume, Bose condensation can occur at a temperature much h igher than the mass of the particle. We can then use a three dimensional ef fective theory to study the thermal properties. We compute the transition t emperature for a complex scalar field theory with a small interaction param eter. (C) 1999 Elsevier Science B.V. All rights reserved.