Séminaire IQ: Sayonee Ray
Date : 17 February 2020 10:45
Type : Institut Quantique
Location : D4-2020
"Center for Quantum Information andControl (CQuIC)"
Université du Nouveau-Mexique
Invitée par Guillaume Duclos-Cianci
Title: Accessing different topologicalclasses and types of Majorana edge states in 1D p-wave superconductors usingperturbations
Abstract: The study oftopological classes and their associated edge states has been of ongoinginterest. In one dimension, the standard platform of these studies has been theconventional Kitaev wire and its realizations. Much less have been explored inother platforms. In this work, we study the edge states of p-wavesuperconductors in 1D, in the presence of perturbations, like a Zeeman fieldand s-wave SC. Firstly, we show that the unperturbed p-wave superconductor byitself can have two types of Majorana edge states, depending on the value ofthe effective chemical potential. When $mu > 1/2$, these are dampedoscillating (Type I), and purely decaying (Type II) when $mu < 1/2$. Weshow that additional components like Zeeman field and s-wave term can causetransitions to different symmetry classes, both trivial or non-trivial, andchange the nature of these edge states. In the presence of these perturbations,we show that there are 3 symmetry classes for the first kind of p-wave pairingand 6 for the second kind, some of them being topologically non-trivial.Further, we explore the nature of mid-gap states when we have a junctionbetween two such topological superconductors and their corresponding behaviourwith the phase of the p-wave order parameter. Our work provides a theoreticalframework of the different ways to get non-trivial topological classes in ap-wave superconductor, using experimentally feasible perturbations.