Applications of Continuum Theory

Abstract

In this chapter we treat some important physical phenomena in terms of continuum theory. First of all we pay attention to the observed textures, for which the orientational field around the appearing discontinuities can be calculated. Two relevant discontinuities are dealt with, namely the orientational field around an axial and around a perpendicular disclination line. Then the thermal fluctuations of the orientational field are discussed and the quantitative validity of the present formulation of the fluctuation theory is examined. Next the strong scattering of light in the nematic phase is explained in terms of the thermal fluctuations of the components of the orientational tensor order parameter. Then we discuss the optical properties of chiral nematics. The observed Bragg reflection, the polarization of the reflected light and the rotary power are dealt with in some detail. Finally the absence of true long-range correlation in the smectic A phase is considered.