We study the interplay of topology and geometry with chirality for several passive and active systems, employing both analytical and numerical methods.

Topology is an emerging field within many scientific disciplines, even leading to a Physics Nobel Prize in 2016. Leiden physicist Marcello Caio and his colleagues have now discovered the existence of topological currents in analogy to electric currents. Publication in Nature Physics on January 14th.

The team of Alireza Mashaghi at the Leiden Academic Centre for Drug Research has found a way to determine and classify the shape of proteins. Their new theory defines the topology of proteins as a simple and precise barcode that allows the identification of all types of folds. ‘This barcode enables…

A new computer simulation shows the promising possibilities of the booming field of topology. Smartly designed mechanical structures carry sound exclusively one way and are immune to fabrication errors. Publication on 17 July in Nature Physics.

The overarching goal of this thesis is to set the foundations, but also make the first essential steps towards establishing a comprehensive, mesoscopic, hydrodynamic theory of epithelial tissues. The stage is set by an exhaustive study of topological defects in passive p-atic liquid crystals, singularities…

A specifically designed collection of gears is soft on one end and rigid on the other. These are robust properties of the system that hold even in the presence of manufacturing imperfections. This emerging research area may lead to new ways of designing geared devices like satellite trackers or watches.…

This thesis studies the geometry of representation varieties and character stacks. These are spaces parametrizing the representations of a finitely generated group, typically the fundamental group of a compact manifold, into an algebraic group G.

Errors are everywhere, and mechanical failures are especially common: buckled grain silos and cracked support columns are, justly, seen as an issue to be avoided.

Alireza Mashaghi and his research team have created a new framework to understand shapes of proteins and DNA. With this framework, many diseases can be understood better.

Publication in Proceedings of the National Academy of Sciences.

Alex Colling himself calls his bachelor's thesis ‘the highlight of his time in Leiden’. And according to his supervisors, that resulted in an outstanding thesis, with great attention to detail. The Mathematics and Physics student worked on a mathematical description of monopoles: hypothetical particles…