NBIA CMT Seminar (note special day and time): Jeffrey Teo (UIUC)
Majorana bound states (MBS) are zero energy point-like excitations that support robust non-local storage of quantum information and non-abelian unitary operations. These exotic properties are essential requirements of a topological quantum computer. MBS were predicted to be present at magnetic flux vortices in spinless chiral p-wave superconductors. We show that MBS can also arise at ``gravitational" vortices in the form of lattice defects, such as dislocations, disclinations and corners, in a wider class of topological crystalline superconductors. We completely classify these BCS superconductors in two dimensions with discrete crystalline symmetries, and propose a criterion that determines the existence of MBS at a defect. This predicts the appearance of MBS at lattice defects in superconducting strontium ruthenate, regardless of its controversial pairing nature, and also doped graphene or silicene, which are single layers of carbon or silicon.