Majorana bound states and parity transitions in S-TI-S lateral Josephson junctions

It is predicted that lateral Josephson junctions fabricated by depositing electrodes of a conventional superconductor (S) on the surface of a 3-D topological insulator (TI), exhibit Majorana bound states (MBS) at the cores of the Josephson vortices.  Here we present experimental results and compare to modeling of MBS features in Nb-Bi₂Se₃-Nb junctions. We show evidence of MBS including node-lifting and features in the critical current diffraction patterns at certain magnetic fields where the MBS enter the junction.  Features of MBS may also be captured in asymmetric dc SQUID (Superconducting Quantum Interference Device) measurements designed to measure the current-phase relation of the junctions. We also report progress on experiments to probe the parity states of MBS pairs by studying the critical current distributions of the S-TI-S junctions. Data and comparison with simulations show that such measurements can provide information on MBS parity states and their lifetimes, which is crucial for applications of MBS based topologically protected quantum computing.