Geodesic geometry of 2+1-D Dirac materials subject to artificial, quenched gravitational singularities

The spatial modulation of the Fermi velocity for gapless Dirac electrons in quantum materials is mathematically equivalent to problem massless fermions on a certain class curved spacetime manifolds. We study null geodesic lensing through these manifolds, which are dominated by curvature singularities, such as nematic singularity walls (where cone flattens along one direction). Null geodesics lens across walls, but do so perfectly collimating local transit angle. Nevertheless, can trap into stable or metastable orbits characterized repeated transits. speculate about role induced one-dimensionality bound 2D dirty d-wave superconductivity.