NUMERICAL OBSERVATION OF A TUBULAR PHASE IN ANISOTROPIC MEMBRANES

We provide the first numerical evidence for the existence of a tubular phase, predicted by Radzihovsky and Toner (RT), for anisotropic tethe red membranes without self-avoidance. Incorporating anisotropy into th e bending rigidity of a simple model of a tethered membrane with free boundary conditions, we show that the model indeed has two phase trans itions corresponding to the flat-to-tubular and tubular-to-crumpled tr ansitions. For the tubular phase we measure the Flory exponent nu(F) a nd the roughness exponent zeta. We find nu(F) = 0.305(14) and zeta = 0 .895(60), which are in reasonable agreement with the theoretical predi ctions of RT; nu(F) = 1/4 and zeta = 1.