LONG-RANGE ELASTIC FORCES BETWEEN MEMBRANE INCLUSIONS IN SPHERICAL VESICLES

We compute the elastic interaction between two identical conical inclu sions in a spherical vesicle. We find it always repulsive and proporti onal to the square of the contact angle. At small angular separations Theta it decays as Theta(-4), as in the case of planar membranes. Afte r a crossover Theta(c) similar to psi(0.54) where psi is the inclusion s' aperture, it decays as Theta(-0.33), yielding a much stronger force than in a flat membrane. Finally, a quadratic minimum around the anti -polar configuration Theta = pi is reached.