Ph.D. Theses

Synchrotron radiation sources and free-electron lasers have revolutionised the study of matter and biological systems by providing unique combinations of radiation pulse characteristics. Although these two types of facilities differ fundamentally in terms of pulses time scales, coherence properties, and (peak) brilliance, each offers an exceptional mix of these features. [...]

Die Untersuchung der Wechselwirkung von Röntgenstrahlen mit biorelevanter Materie ist ein anhaltendes und weitverbreitetes Forschungsfeld. Obwohl die makroskopischen Folgen dieser Wechselwirkung bereits weitgehend verstanden sind, ist unser Verständnis der Prozesse auf molekularer Ebene noch sehr unzureichend. [...]

In recent years, perovskite nanocrystals (CsPbX3, with X = Cl, Br, I) have emerged as a new class of materials for photonic and optoelectronic applications due to their exceptional synthetic scalability through solution-based processes, room-temperature fabrication and remarkable physical properties such as high emission efficiency and defect tolerance. Additionally, these materials possess tunable optical properties through controlled adjustments of their size and composition. [...]

The integrability properties of $\mathcal{N}=4$ Super-Yang-Mills in the planar limit have been studied extensively and are well understood. For certain classes of theories, obtained by orbifolding $\mathcal{N}=4$ Super-Yang-Mills, it was shown that planar integrability is actually inherited and persists at the orbifold point. [...]

The study of radio galaxies (RGs) offers valuable insights into the complex dynamics between active galactic nuclei (AGN), host galaxies, and the surrounding medium. Among the diverse population of RGs, giant radio galaxies (GRGs) have a linear extent larger than 700 kpc and they are relatively rare compared to smaller RGs. [...]

Ultraviolet (UV) light plays a crucial role across various scientific fields such as biochemistry, material science and nanotechnology. Producing and using UV pulses with sub-5 fs durations is extremely demanding, but offers new possibilities for studying electron dynamics in light-induced biochemical re- actions.This thesis presents a tuneable ultrafast UV source operating at high repetition rates (up to 50 kHz), designed to be the key component of a table-top few-femtosecond UV-pump and IR-probe beamline to perform time-resolved spectroscopy measurements. [...]

This thesis work presents the first searches and the first evidences for the $_{t}WZ$ and $_{t}W_γ$ processes at the LHC with the CMS experiment. The analyses employ proton-proton collision data corresponding to an integrated luminosity of 138 fb$^{−1}$ collected during Run 2 of the LHC between 2016 and 2018. [...]

Antibiotic resistance in Gram-negative bacteria, especially Pseudomonas aeruginosa, presents significant challenges in treating infections, particularly in hospitalized and immunocompromised patients. This pathogen secretes various virulence factors, including phospholipases, which play critical roles in its pathogenicity.This study focused on characterizing two phospholipases, PLCH and PLCN. [...]

This thesis is concerned with consistency, robustness and sparsity of supervised and semi-supervised learning algorithms. For the latter, we consider the so-called Lipschitz learning task (Nadler, Boaz, Nathan Srebro, and Xueyuan Zhou. [...]