Title: Global solution of 2D hyperbolic liquid crystal system for small initial data

Abstract: We prove the global stability of small perturbation near the the constant equilibrium for the two dimensional simplified Ericksen-Leslie's hyperbolic system for incompressible liquid crystal model, where the direction function of liquid crystal molecules satisfies a wave map equation with an acoustical metric. This improves the almost global existence result by Huang-Jiang-Zhao. As byproducts, we obtain the sharp (same as the linear solution) decay estimates for the nonlinear velocity and the nonlinear wave part. Moreover the nonlinear wave part scatters to a linear solution as time goes to infinity.
The main novelty of this paper is that we uncover a null structure inside the velocity equation on the Fourier side for the nonlinear interaction between nonlinear heat equation and nonlinear wave equation.