Black hole mirages in Weyl semi-metals: Electron lensing and Berry curvature effects

In this talk I present a work with my collaborators where we have studied inhomogeneously strained/tilted Weyl semi-metals in relation to black-hole analogies, using a combination of analytical and numerical techniques. We showed that an analog of ‘black-hole photon sphere’ termed as ‘the separatrix’ forms a boundary beyond which semi-classical methods fail to predict the behaviour of lensed wave-packet trajectories in a lattice system and thus also marks the regime of failure of black hole analogies in such systems. The separatrix also forms a ‘filter’ that sorts trajectories into deflected versus spiralling based on the initial momentum of injection into the system. Our analytical results could be used to precision-engineer deflection and chirality-selection of electron trajectories in inhomogeneous Weyl semi-metal based quantum devices. We also showed that the precession dynamics of the ‘spin/chirality’ of the Weyl-particle underlies the well-known Berry curvature induced anomalous shifts and it leads to drastic deviations from classical geodesic trajectories of massless particles (something which is not well appreciated in gravitational physics literature as well).