Some comments on unitary qubit lattice algorithms for classical problems

$\bf{Abstract}$: A qubit lattice algorithm (QLA), which consists of a set interleaved unitary collision-streaming operators, is developed for electromagnetic wave propagation in tensor dielectric media. External potential operators are required to handle gradients the refractive indices, and these typically non-unitary. similar problem arises QLA Korteweg-de Vries equation, as operator that models KdV nonlinear term also Several QLAs presented here avoid need this non-unitary by perturbing collision operator. These fully unitary.