RENORMALIZATION GROUP THEORY OF THE INTERACTING BOSE FLUID

F.W. Wiegel

Richard J. Creswick, F.W. Wiegel

F.W. Wiegel

G. Alber, G. Metikas

The renormalization group is not only a powerful method for describing universal properties of phase transitions but it is also useful for evaluating non-universal thermodynamic properties beyond meanfield theory. In this contribution we concentrate on these latter aspects of the renormalization group approach. We introduce its main underlying ideas in the familiar context of the ideal Bose gas and then apply them to the case of an interacting, confined Bose gas within the framework of the random phase approximation. We model confinement by periodic boundary conditions and demonstrate how confinement modifies the flow equations of the renormalization group changing thus the The recent experimental realization of Bose-Einstein condensation has renewed the interest in the study of trapped, dilute, weakly interacting Bose gases. Despite the long history of this subject there still exist unresolved

SUJIT SARKAR

We present the study of Kondo effect in an interacting quantum wire. We mainly emphasize the effect of strong electronic correlations in the study of renormalization group flow diagram and the stability analysis of fixed points for both magnetic and nonmagnetic impurities. We observe that the behavior of the system is either in the single channel or in the two channel Kondo effect, depending on the initial values of coupling constants and strong correlations.

F. O. Coelho, J. A. Plascak

The new mean field renormalization group is used to study the Ising model through the calculation of the order parameter by means of the effective field theory based on Callen–Suzuki identity. By considering one- and two-spin clusters, better results are obtained when compared to the previous treatment using the usual mean field approximation.