Tunneling density of states in exotic superconductors and spatial patterns of particle-hole interference

Tunneling spectroscopy of superconductors offers rich insights into gap symmetry, quasiparticle dynamics, and pairing glue. This talk describes spatial interference patterns in the tunneling density of states (TDOS) that appear near localized magnetic adatoms. The interference arises because Bogoliubov quasiparticles are coherent superpositions of electrons and holes with opposite spins, allowing coherent and reversible particle-to-hole conversion within the superconductor bulk. Magnetic adatoms act as beam splitters, enabling interference between particle and hole states, leading to spatial patterns reminiscent of Young's double-slit experiment. In topological superconductors, these interference patterns are further modulated by nodal lines that encode the winding numbers of the gap function phase. For spin-dependent tunneling, we find a connection between TDOS and spin chirality due to fermion stirring [A. Panigrahi, V. Poliakov, Z. Dong, L. Levitov, arXiv:2407.17433]. Similar to TDOS, chirality exhibits Young's interference patterns and nodal lines reflecting the topological nature of the gap phase, providing a unique tool to probe topological superconductivity.