Theses
Coherent thermodynamics and transport properties of mesoscopic Josephson junctions
The thesis discusses three topics investigated during the PhD. The first topic is equilibrium thermodynamics of a hybrid superconductor/normal metal junction, where the Maxwell relation between supercurrent and entropy in a junction is investigated on a statistical mechanism of quasi-particles. These findings can be used to build up a complete thermodynamic description with processes and cycles based on supercurrent, temperature, superconducting phase, and entropy. The second topic of the thesis is Peltier refrigeration of superconductor/graphene device and its bolometric characteristics. The low electron-phonon coupling and the low heat capacity of graphene allow reaching a low base temperature and a fast thermal response. The third topic consists of nano-fabrication and characterization of a superconducting interferometer based on gating of two constriction-junction. We demonstrate an unconventional relationship between the switching current and the gating field. A phenomenological model simulates the experimental results.
Coherent charge transport in a three-terminal Josephson junction: the omega-SQUIPT
This thesis concerns the realization and electrical characterization of a Josephson interferometer based on a proximized three-terminal weak link. The tunnel spectroscopy measurements reveal transitions between gapped (insulating) and gapless (conducting) states, controlled by the phase configuration of the three superconducting leads connected to the junction. Our observation of the gapless state is pivotal for enabling phase engineering of different and more sophisticated artificial topological materials.
Propagazione di pacchetto d'onde (wavepacket propagation)
This thesis consists of the development of a series of MatLab scripts able to perform numerical simulations of the Schrödinger equation in the case of a single particle in one dimension with arbitrary potentials. The numerical results are then used to produce videos showing the quantum wave-packet propagation through a potential barrier or in a potential box.