Some consequences of the Ginsburg-Landau-de Gennes gradient term in smectics

We work out some consequences of the Ginsburg-Landau-de Gennes gradient term on the properties of smectic liquid crystals. (i) Disclinations in smectic C are very much like vortex filaments in superfluids or magnetic fluxoids in superconductors. (ii) A uniform distortion of the phase factor lowers the C-A (or A-N) transition point, and at any given temperature there should occur a second order transition beyond a critical distortion. (iii) Light scattering due to phase fluctuations in smectic C should be strongly temperature dependent. (iv) In smectic A of finite size the phase change under an imposted δ×n→ distortion can be of second order