Analysis of the Thermodynamic Potential

Abstract

The phenomenological method of analyzing phase transitions is based on the construction of a thermodynamic potential Φ which may be represented as a polynomial expansion

$$ \Phi = \sum\limits_n {{P_n}} \left( {\left\{ \eta \right.} \right.\left. {\left. \lambda \right\}} \right),$$

(11.1)

where P _n ({η _λ }) are homogeneous polynomials of degree n invariant under the initial-phase symmetry group G. The quantities η _λ , which are OP’s, transform according to the group G IR D ^ν responsible for the symmetry change at the phase transition.