Colloquia Archive 2018

The reionization of the intergalactic medium (IGM) is one of the last mostly unexplored frontiers is observational astrophysics. In this talk I will discuss some recent developments in the theoretical modeling of the process which will aid the interpretation of upcoming observations. I will also present prospects in the detection ...

The matter present in our universe is dominated by a component which has the properties of a non-relativistic collisionless fluid, dubbed dark matter (DM). This claim assumes that General Relativity (GR) holds on cosmological scales, currently a reasonable hypothesis, while extensions of GR are also investigated. Standard particle and nuclear ...

In our everyday experience, the mass of an object is the sum of the mass of its parts. However, in the world of subatomic particles, this everyday assumption is no longer true and even very small mass differences can have cosmic consequences. After an introduction to the mechanisms by which ...

Soft elastic interfaces exhibit intriguing similarities to liquid interfaces: they possess a surface tension and are susceptible to interfacial instabilities. The first part of this talk addresses how soft solids behave when exposed to liquid drops, which provide a singular forcing. It is shown that such "soft wetting" fundamentally differs ...

The coupling of baryons and photons by Thomson scattering in the early universe leads to a rich structure in the power spectra of the cosmic microwave background photons and the matter. The study of these "echoes of gravity" has revolutionized cosmology and allowed precise measurement of a host of important ...

This talk will show that bacterial suspensions, beyond their intrinsic, dominating importance in biology, are also excellent systems to explore and test theoretical results on active matter, I will present recent experimental results on dense bacterial suspensions obtained in the groups of Masaki Sano (University of Tokyo), Yilin Wu (Chinese ...

Long-range enhancers - found as far away as 1 megabase from their target gene - are key in controlling precise spatial and temporal gene expression in mammals. In contrast to the 20,000 or so genes in our genome, there may be hundreds of thousands, or even millions, of enhancers. Deletion, translocation ...

Jets at particle colliders are our window into fundamental reactions that sometimes proceed through confined degrees of freedom that are invisible at long distances. I'll review some of the history and theory of particle jets, and how they reflect a crossroads between classical and quantum phenomena.

Massive black holes, weighing millions to billions of solar masses, inhabit the centers of today's galaxies. Black hole masses typically scale with properties of their host galaxies, such as mass and velocity dispersion. The progenitors of these black holes powered luminous quasars within the first billion years of the ...

I will review new developments in lattice simulations in kaon physics designed to explore the limits of the Standard Model and to search for signatures of new physics. For the decays of kaons (and pions) into leptons, the precision of lattice computations is now such that electromagnetic and strong isospin-breaking ...

Active materials such as bacteria, molecular motors and self- propelled colloids, are Nature's engines. They continuously transform chemical energy from their environment to mechanical work. Dense active matter shows mesoscale turbulence, the emergence of chaotic flow structures characterised by high vorticity and motile topological defects. I shall describe flow ...

I will discuss the weak scale hierarchy problem from a known, but less mainstream, direction and I will argue that the hints we have observed for high energy physics may in fact be a smokescreen, with the new physics responsible for these hints lying much closer to accessible energies. In ...

The talk will discuss how the observed structure in the evolved (last 1 Gyr) Universe offers a unique probe of fundamental physical theories operating on cosmological scales. The focus will be on implications of deviations of motions of galaxies from a pure Hubble flow of the cosmic background. While the ...