TOPOLOGICAL DEFECTS IN LIQUID CRYSTALS

Topological defects in liquid crystals

Topological defects are singularities which appear in a broad range of fields such as liquid crystals, biology, cosmology, and particle physics. They appear as result of a spontaneous symmetry breaking¹. In nematic liquid crystals, a soft matter that has properties of both liquid and solid crystal, topological defects are called disclinations and are formed in the transition between the isotropic and the nematic phase². In this seminar, I talk about topological defects in general, then concentrate on their formation in liquid crystal, as well as common types in this media. I finish with discussion about lensing effects and scattering caused by changes in the order parameter field^3,4.

References:

[1] S. Fumeron, and B. Berche. “Introduction to topological defects: from liquid crystals to particle physics.” The European Physical Journal Special Topics (2023): 1-21.

[2] I. Chuang, et al. “Cosmology in the laboratory: Defect dynamics in liquid crystals.” Science 251.4999 (1991): 1336-1342.

[3] C. Sátiro, and F. Moraes. “Lensing effects in a nematic liquid crystal with topological defects.” The European Physical Journal E 20 (2006): 173-178.

[4] S. Fumeron, F. Moraes, and Erms Pereira. “Retrieving the saddle-splay elastic constant K 24 of nematic liquid crystals from an algebraic approach.” The European Physical Journal E 39 (2016): 1-11.