We present a significant improvement to a complex time-dependent WKB (CWKB) formulation developed by Boiron and Lombardi [J. Chem. Phys. 108, 3431 (1998)] in which the time-dependent WKB equations are solved along classical trajectories that propagate in complex space. Boiron and Lombardi showed that the method gives very good agreement with the exact quantum mechanical result as long as the wa...

Graphene bilayers exhibit zero-energy flat bands at a discrete series of magic twist angles. In the absence intra-sublattice inter-layer hopping, states satisfy Dirac equation with non-abelian SU(2) gauge potential that cannot be diagonalized globally. We develop semiclassical WKB approximation scheme for this by introducing dimensionless Planck's constant proportional to angle, solving lineari...