Weyl time evolution operator in planar Bianchi-type-I universes

In this paper, Dirac’s equation in anisotropic Bianchi-type-I background spacetimes is treated with respect to orthonormal frames. By specializing the massless spinor case and metrics power-law scale factors planar symmetry, an analytical expression of approximate time evolution operator (TEO) derived. use operator, all solutions can be generated. construction, these agree asymptotically at early times exact solutions. The approach also well adapted for studying small deviations from conformally flat backgrounds. particular, it shown that limiting vanishing anisotropy renders correct result.