On the Influence of Majorana Bound States in Quantum-Rings
Fabián Gonzalo Medina Cuy

Universidad Técnica Federico Santa María

Comisión de Tesis
Dr. Pedro Orellana (USM), Profesor guía
Dr. Luis Rosales (USM), Profesor Co-tutor
Dra. Mónica Pacheco (USM), Evaluadora interna
Dr. Eric Suárez (USM) Evaluador interno
Dr. Rodrigo Soto (PUC), Evaluador externo

Abstract: A key characteristic in topological superconductivity is the presence of a boundary state located at zero energy. This state receives the name of Majorana zero mode, being a particle which is its own antiparticle. The detection of such a state has been very elusive, since the existence of Andreev bound states can mimic the zero energy mode. In this work we focus in the study of onedimensional nanowires in its topological phase hosting Majorana modes at its ages and coupled to a quantum-ring. The quantum-ring with a crossed magnetic field provides an observable current. Unfortunately, this signal is not suitable for detecting Majorana zero modes. Nevertheless, Majorana modes oscillate when there is an overlapping between them and the manifesting zero energy crossings, which are protected topologically. Hence, persistent currents could be able to detect zero energy crossings by its discontinuity. With the presence of Rashba spin-orbit coupling we can shift the zero energy crossings in the parameter space, these zero energy crossings may be detected with both persistent current and spin current, where the presence of this last one is an indication of spin asymmetry, a key ingredient in the existence of Majorana. Finally, the quantum-ring between two topological superconductors is also considered. In this last case, topological patterns appear in the two-dimensional parameter space, formed by the magnetic flux and the superconducting phase difference. Such patterns can be also detected by dc Josephson currents as well as persistent currents. The interplay between these two currents is also studied.

Viernes 5 de noviembre 11:00 hrs.

Transmisión de Zoom: https://us02web.zoom.us/j/88393686017?pwd=L3k3cW12MzJJZmpOMXBBQm81bExnUT09

ID de reunión: 883 9368 6017
Código de acceso: 280435

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