Thermodynamic properties of confined interacting Bose gases: A renormalization-group approach - art. no. 023613

A renormalization-group method is developed with which thermodynamic proper ties of a weakly interacting, finite-size Bose gas can be investigated. The reby effects originating from a confining potential are taken into account by periodic boundary conditions and by treating the resulting discrete ener gy levels of the confined degrees of freedom properly. The resulting densit y of states modifies the flow equations of the renormalization group in mom entum space. It is shown that as soon as the characteristic length of confi nement becomes comparable to the thermal wavelength of a weakly interacting and trapped Bose gas its thermodynamic properties are changed significantl y. This is exemplified by investigating characteristic bunching properties of the interacting Bose gas which manifest themselves in the second-order c oherence factor.