Bubble Domain Texture of a Liquid Crystal

Abstract

We modify the Sakai-Sugimoto model of chiral symmetry breaking to take into account the open string tachyon which stretches between the flavour D8-branes and D8-branes. There are several reasons of consistency for doing this: (i) Even if it might be reasonable to ignore the tachyon in the ultraviolet where the flavour branes and antibranes are well separated and the tachyon is small, it is likely to condense and acquire large values in the infrared where the branes meet. This takes the system far away from the perturbatively stable minimum of the Sakai-Sugimoto model; (ii) The bifundamental coupling of the tachyon to fermions of opposite chirality makes it a suitable candidate for the quark mass and chiral condensate parameters. We show that the modified Sakai-Sugimoto model with the tachyon present has a classical solution satisfying all the desired consistency properties. In this solution chiral symmetry breaking coincides with tachyon condensation. We identify the parameters corresponding to the quark mass and the chiral condensate and also briefly discuss the mesonic spectra.

Liquid crystal bubbles forming a tunable micro-lenses array

“…These bubbles can arrange themselves in hexagonal arrays. Such formation of bubble arrays was observed for the first time in 1974, simultaneously by both Kawachi et al 17 and Haas et al 18 in liquid crystal materials with negative dielectric anisotropy. Both groups noted that CLCN bubbles were generated by applying a DC or AC electric pulse strong enough and with a suitable frequency to induce electrohydro-dynamical effects.…”

Subnanowatt Opto‐Molecular Generation of Localized Defects in Chiral Liquid Crystals

“…Such developments can be viewed as spatially controlled versions of randomly distributed defect structures generated by uniform quasistatic electric fi elds as shown in Refs. [ 8,9 ] four decades ago, see also Ref. [ 10,11 ] for more recent works.…”

Theory of skyrmion states in liquid crystals

“…2, 3, 4) illustrating the basic features of confined chiral modulations and demonstrating a fundamental role of axisymmetric strings (6), (7)) in the formation of two-dimensional solitonic states in thin layers of chiral liquid crystals. Multi-dimensional modulated textures observed in confined chiral liquid crystals consist of 2D nonsingular axisymmetric strings (skyrmions proper) 20 and 2D and 3D localized structures including different types of point defects and dislocations [20][21][22][23][24][25][26] . The former are described by solutions of Eqs.…”

“…During last four decades a rich variety of 2D and 3D localized structures with different types of singularities have been observed in confined chiral liquid crystals as cholesteric bubbles (spherulitic domains) 21,22 , cholesteric fingers 22,23 , torons 24,25 , and other specific solitonic textures 26 .…”