SELF-AVOIDING TETHERED MEMBRANES AT THE TRICRITICAL POINT

The scaling properties of self-avoiding tethered membranes at the tric ritical point (Theta-point) are studied by perturbative renormalizatio n group methods. To treat the 3-body repulsive interaction (known to b e relevant for polymers), new analytical and numerical tools are devel oped and applied to 1-loop calculations, These techniques are a prereq uisite to higher-order calculations for self-avoiding membranes. The c rossover between the 3-body interaction and the modified 2-body intera ction, attractive at long range, is studied through a new double epsil on-expansion. It is shown that the latter interaction is relevant for 2-dimensional membranes at the Theta-point.