Electric-field coupling to nematic order
= Electric-field coupling to nematic order
{title2=$-\chi E_iQ_{ij}E_j$}
The leading scalar coupling of an <electric field> to the <nematic order parameter> is quadratic in the field and linear in the tensor. For <uniaxial nematic order>, it is $-3\chi\lambda E^2(\cos^2\vartheta-1/3)/2$. When $\chi\lambda>0$, minimization aligns the <nematic director> with the field axis and adds $-\chi E^2\lambda$ to the scalar <Landau free energy>.