Remarks on the n=1/2 disclination line in Landau-de Gennes theory of nematic liquid crystals

Abstract

Using Landau-de Gennes effective theory for nematic liquid crystals we analyse the structure of rectilinear n=1/2 smooth disclination line in the case of equal elastic constants. We find that at certain temperature there is an exact mathematical correspondence with a rectilinear vortex in superfluid $^4He$. With a help of polynomial approximation difference of free energies of the smooth and of a singular disclination lines is estimated. It turns out that the smooth disclination line is energetically preferred only if temperature is low enough. At higher temperatures a disordered core should be expected.