Figure 2: Weyl points in an inversion symmetry breaking structure.
From: Photonic Weyl point in a two-dimensional resonator lattice with a synthetic frequency dimension
(a) Modulation phase Ï•A=0, Ï•B=Ï€ leads to inversion symmetry breaking. (b) The Weyl points in the reciprocal space and their charges. The Weyl points are located at ky=0, 
and kf=±
. (c) The band structure in kx−kf plane at ky=0. The Weyl points at 
are equivalent to those at 
in b. (d) The band structure in ky−kf plane at 
. The charge of each Weyl point is shown underneath.
