Electrodynamics of Quantum-Critical Conductors and Superconductors

TL;DR

This thesis investigates quantum-critical superconductivity through optical experiments on various materials, linking experimental results with theoretical models to deepen understanding of superconducting states near quantum critical points.

Contribution

It offers a unified experimental and theoretical framework for understanding quantum-critical superconductivity across different disordered and heavy-fermion materials.

Findings

Optical measurements reveal signatures of quantum-critical behavior in NbN, Al, and CeCoIn5.

Theoretical models successfully interpret the experimental data, bridging experiment and theory.

The work advances understanding of superconductivity near quantum critical points.

Abstract

This thesis presents and discusses optical low-temperature experiments on disordered NbN, granular Al thin-films, and the heavy-fermion compound CeCoIn5, offering a unified picture of quantum-critical superconductivity. It provides a concise introduction to the respective theoretical models employed to interpret the experimental results, and guides readers through in-depth calculations supplemented with supportive figures in order to both retrace the interpretations and span the bridge between experiment and state-of-the art theory.