Light matter interaction in mesoscopic systems

The study of light-matter interaction has led to many fundamental discoveries as well as to the development of new technology. In this thesis, we investigate the interaction between light and matter in different mesoscopic systems such us Fabry-Perot cavities with fixed and/or moving mirrors (optomechanical cavities) and superconducting circuits. In the context of optomechanical cavities, we isolate genuine quantum contributions of the interaction between an optical field and a mechanical mirror and study how to probe nonlinearities of the mechanical motion. We also investigate dynamical corrections, arising from an initial non-equilibrium configuration of the system, to the Casimir energy induced by the interaction between a quantum multimode field and the quantum fluctuations of the movable mirror. In a cavity scenario, we further consider such kind of dynamical corrections for the Casimir-Polder force between an excited atom and a perfectly conducting mirror, finding new features that can allow for an easier way to single-out the dynamical Casimir-Polder effect. In the context of superconducting circuits, we explore the light-matter interaction between microwave fields and artificial atoms in the ultrastrong coupling regime, where the system displays a high degree of entanglement. We show how to extract these (otherwise inaccessible) quantum correlations, and how such correlations can potentially be exploited as a resource for entanglement-based applications. In all these investigations we provide feasible experimental scenarios where such new effects can be probed.Open Acces

Dynamical Systems

Complex systems are pervasive in many areas of science integrated in our daily lives. Examples include financial markets, highway transportation networks, telecommunication networks, world and country economies, social networks, immunological systems, living organisms, computational systems and electrical and mechanical structures. Complex systems are often composed of a large number of interconnected and interacting entities, exhibiting much richer global scale dynamics than the properties and behavior of individual entities. Complex systems are studied in many areas of natural sciences, social sciences, engineering and mathematical sciences. This special issue therefore intends to contribute towards the dissemination of the multifaceted concepts in accepted use by the scientific community. We hope readers enjoy this pertinent selection of papers which represents relevant examples of the state of the art in present day research. [...