Dynamics of dissipative solitons in nematics

Solitons are localized travelling waves that were first discovered in a shallow canal by Russell in 1834 ¹. They are ubiquitous and exist in various areas of physics, such as nonlinear photonics, magnetic matter, superconductors and cosmology ². However, producing multidimensional solitary states and manipulation of their motion are still large challenges. Liquid Crystals (LCs) are self-organized anisotropic fluids. The coupling between the molecular orientation, the director, and the fluid velocity of LCs introduces a nonlinear term in the director equation of motion, which leads to the possible existence of solitons ³. In this work, we describe the formation of dynamic multidimensional solitons in nematics with negative and positive dielectric anisotropies, respectively. These solitons are self-confined director perturbations that propagate rapidly through the LC bulk and preserve their identities after collisions. We tune the velocity of the solitons by electric fields and control their trajectories through alignment layers. We also show that these solitons can be used as vehicles for 2D delivery of micro-cargos.

1 Dauxois, T. & Peyrard, M. Physics of solitons, (Cambridge University Press, 2006).

2 Kartashov, Y. V., Astrakharchik, G. E., Malomed, B. A. & Torner, L., Nature Reviews Physics, 1, 185-197 (2019).

3 Lam, L. & Prost, J. Solitons in liquid crystals, (Springer Science & Business Media, 2012).