Nematic twist
= Nematic twist
{title2=$K_2(\mathbf n\cdot\nabla\times\mathbf n)^2/2$}
<Nematic twist> rotates the <nematic director> around an axis perpendicular to it. The helix $\mathbf n=(\cos qz,\sin qz,0)$ has zero <nematic splay> and <nematic bend>, and twist density $K_2q^2/2$.