Physical temperature and pressure in fully nonextensive statistical thermodynamics

This paper generalizes previous results concerning the definitions of physical temperature and pressure in nonextensive statistical thermodynamics. The novelty is that both the internal energy and the volume are no longer additive functions. The new approach is referred to as "fully" nonextensive thermodynamics. The physical temperature is different from the inverse of the Lagrange multiplier. This fact changes the form of some usual thermodynamic relations. For example, the Clausius definition of the thermodynamic entropy has to be modified. As an application, the classical gas model is examined with statistical calculations performed under the Tsallis-Mendes-Plastino formalism of nonextensive thermodynamics. The specific heat expression differs from the one encountered in ordinary extensive thermodynamics but the equation of state keeps the same form.