Probing helical vs chiral character of topological superconductors via non-local Hanbury-Brown and Twiss correlations.

Topological superconductors host surface Andreev bound states which can be classified as chiral or helical. Chiral superconductors belong to $Z$ symmetry class which breaks time-reversal symmetry (TRS) while helical superconductors belong to $Z_2$ symmetry class which preserves TRS. Chiral and helical superconductors can be further categorized by the parity-even or odd, of their order parameter. In this paper using Hanbury Brown and Twiss (HBT) shot noise correlations and the non-local conductance, we probe metal/unconventional superconductor/metal junctions in order to better understand the pairing helical vs chiral in topological superconductors. We also compare these to non-topological superconductors. Topological superconductors are carriers of Majorana fermions which are important for topological quantum computation. By distinguishing chiral superconductors, wherein Majorana bound states (MBS) persist even in presence of a magnetic field, from helical superconductors where MBS are fragile, our study will help in the search for stable Majorana fermions which will be useful for topological quantum computation.