CDQT Guest Seminar: Synthesizing quantum matter with magnetic and nonmagnetic adatoms on superconductors — the topological secrets of hybridizing Machida-Shibata states

Guest Seminar hosted by CDQT.
Speaker: Dr.Thore Posske(University of Hamburg)
Title: Synthesizing quantum matter with magnetic and nonmagnetic adatoms on superconductors — the topological secrets of hybridizing Machida-Shibata states

https://oist.zoom.us/j/92902637747?pwd=QVRsj3WXENvTUeczROgjT7UXjrjio4.1

Abstract: By manipulating adatoms on the surface of clean superconducting substrates, quantum states as a basis for quantum technological applications can be engineered. Here, the superconductor's quasiparticle gap effectively protects against low-energy fermionic excitations. I will give an overview of the foundations and the status of the field and then focus on hybridizing Machida-Shibata states. These are spin-degenerate "particle-in-a-box" states on superconductors. Hybridizing them can in principle create topological superconductors in class DIII with time-reversal symmetry-protected Majorana modes or edge channels, depending on the dimension of the artificial lattice. Yet, a "no-go theorem" for topological DIII superconductors typically forbids this. I will show that local electron repulsion can circumvent the no-go theorem and resolve the nuances of the topological invariant. For instance, in 1D, we predict a hidden CI-symmetric topological phase. This brings us closer to realizing class DIII topological superconductors and controlling their unique topological boundary modes.

About the speaker: Posske Research Group