Dissertation

On transport properties of Majorana fermions in superconductors: free & interacting

Majorana fermions in superconductors are the subgap quasiparticle excitations that are their own antiparticles.

Author: Gnezdilov, N.V.
Date: 12 June 2019
Links: Thesis in Leiden Repository

Majorana fermions in superconductors are the subgap quasiparticle excitations that are their own antiparticles.They occur on the boundary of so-called topological superconductors and are an equal weight quantum superposition of a positively charged electron and a negatively charged hole, that makes them charge-neutral but not an eigenstate of charge. Thus, the expectation value of charge vanishes, but the fluctuations of charge stay finite.Study of the latter ones would provide a purely electrical detection of Majorana states. In this thesis, we show that the electrical shot noise (the second moment of charge fluctuations) originated from the surface of a three-dimensional topological superconductor is related to the thermal conductance with a coefficient which consists of temperature and fundamental constants.The second part of the thesis is devoted to the strongly interacting fermionic zero modes (both Dirac and Majorana) described by the Sachdev-Ye-Kitaev model, which can be realized in disordered quantum dots in magnetic fields. The theoretical predictions of the spectroscopic properties of such quantum dots are presented in this thesis.