Abstract
We study by Monte Carlo simulation a model of fluid membranes whose Hamiltonian is a linear combination of Gaussian energy S_1 and a squared scalar curvature energy S_3. We find that the model has not only crumpled phases but also a branched polymer phase, and that the model undergoes a first order phase transition between the branched polymer phase and one of the crumpled phases. We find also that the model undergoes a second order phase transition inside the branched polymer phase.
