predict that a TRS breaking WSM state can only be realized in this compound if a canting of the magnetic moment ($\sim$10$^\circ$) from the $c$ axis, resulting in an effective in-plane ferromagnetic component along (110) direction, is assumed in addition to the established AFM ordering. Although such a band structure is in reasonable agreement with the ARPES results, the ad-hoc assumption of canted antiferromagnetism has not been supported by neutron scattering experiments [@FuhrmanPrivateCommunication; @wang2016two]. Moreover, the magnetic space group found via neutron scattering that describes the AFM ordering in YbMnBi$_2$ has a symmetry breaking that does not allow canting of Mn magnetic moments away from the $c$ axis. From general considerations, the only way canting can occur is via an AFM transition that is not second order, or a lattice symmetry that is not tetragonal. Transport measurements reported in [@wang2016two] further supports a quasi two dimensional Dirac dispersion in this compound.

A number of interesting proposals have been made for the optical properties of WSMs [@hosur2013recent]. An ideal 3D Weyl state comprises at least a pair of non-degenerate band crossings in momentum space with the Fermi level at the nodal point. In 3D Dirac or Weyl systems, the joint density 