Chekanova N. А solution of classification problem for equilibrium states in condensed medium with spontaneously broken symmetry using the quasi-average method

A new quantum microscopic approach has been proposed and developed for the classification of uniform equilibrium states of condensed media with spontaneously broken symmetry. The mechanism of emergence of additional continuous and discrete thermodynamic parameters that characterize these states has been determined. A generalization of the developed approach has been given for the problem of classification of non-uniform equilibrium states of degenerate media. This approach has been employed for the study of equilibrium states and classification of quantum liquids with scalar, vector and tensor order parameters, in particular for the superfluid phases of Не-3, solutions of quantum liquids, a superfluid system with d-pairing. Equilibrium states of condensed media with continuously broken spatial symmetry have been investigated, for which the explicit form of the tensor order parameter has been found and the complete set of possible uniform and non-uniform states and the form of spatial and unbroken symmetry generators have been determined. The correspondence between the found solutions for the order parameter and the really existing ordering in liquid crystals has been ascertained. Effective equations for determination of the equilibrium structure of the order parameter have been obtained, that do not imply any assumptions about the free energy form and do not exploit the requirement of temperature closeness to the point of phase transition.