Statistical mechanics of bilayer membrane with a fixed projected area

The surface tension and bending modulus of a bilayer membrane with a fixed projected area was determined using equilibrium and fluctuation method. The equilibrium method is based on the fact that surface tension and bending modulus describes the free energy variations due to area-changing and curvature-forming deformations. The elastic coefficients were extracted from the analysis of the spectrum of thermal fluctuations of the membrane in the fluctuation method. Computer simulations and the numerical values of the elastic coefficients confirm the idea of equivalence between the two routes to membrane elasticity.