We discuss the asymptotic properties of quantum states density for
fundamental p−branes which can yield a microscopic interpretation of the
thermodynamic quantities in M-theory. The matching of BPS part of spectrum for
superstring and supermembrane gives the possibility of getting membrane's
results via string calculations. In the weak coupling limit of M-theory the
critical behavior coincides with the first order phase transition in standard
string theory at temperature less than the Hagedorn's temperature TH. The
critical temperature at large coupling constant is computed by considering
M-theory on manifold with topology R9⊗mathbbT2.
Alternatively we argue that any finite temperature can be introduced in the
framework of membrane thermodynamics.Comment: 16 pages, published in Mod. Phys. Lett. A16(2001)224