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Superconductivity and fermionic dissipation in quantum Hall edges
Add to Calendar 2022-04-11T18:00:00 2022-04-11T19:00:00 UTC Superconductivity and fermionic dissipation in quantum Hall edges Password: 342891
Start DateMon, Apr 11, 2022
2:00 PM
End DateMon, Apr 11, 2022
3:00 PM
Presented By
Noam Schiller, Weizmann Institute of Science, Israel

Proximity-induced superconductivity in fractional quantum Hall edges is a prerequisite to proposed realizations of parafermion zero-modes. A recent experimental work (Gül et al., arXiv: 2009.07836) provided evidence for such coupling, in the form of a crossed Andreev reflection signal, in which electrons enter a superconductor from one chiral mode and are reflected as holes to another, counter-propagating chiral mode. Remarkably, while the probability for cross Andreev reflection was small, it was stronger for $\nu=1/3$ fractional quantum Hall edges than for integer ones. We theoretically explain these findings, including the relative strengths of the signals in the two cases and their qualitatively different temperature dependencies. An essential part of our model is the coupling of the edge modes to normal states in the cores of Abrikosov vortices induced by the magnetic field, which provide a fermionic bath. We find that the stronger crossed Andreev reflection in the fractional case originates from the suppression of electronic tunneling between the fermionic bath and the fractional quantum Hall edges.