Soft matter provides unique opportunities to control and address the dynamics of microscopic particles. This feature is an ambitious challenge in several fields. As examples, it can be employed in material science to direct self-assembly of hierarchically organized structures, or in biology to understand bacteria mobility, biofilm formation or cell adhesion. In this talk I will present studies of colloidal particles dynamics in different environments and show how soft media can affect particles behavior: at air-water interfaces capillarity exerts an additional drag on the particle [1]; at solid interfaces, polymer coatings mediate particle-substrate interactions, providing a tool to trigger adsorption and adjust adsorption rate [2]; in confined cholesteric liquid crystals boundaries mold the energy landscape creating preferred sites for particle location.

[1] G .Boniello et al., Nature materials, 14.9 (2015): 908.
[2] G .Boniello et al., Physical Review E, 97.1 (2018): 012609.

In spite of much effort, many aspects of chromosome segregation in bacteria remain unclear. Like many other bacteria, the chromosomal origin of replication in Escherichia coli is dynamically positioned throughout the cell cycle. Initially maintained at mid-cell, where replication occurs, origins are subsequently partitioned to opposite quarter positions. However the mechanism underlying this is unknown. Here, we provide an explanation based on the self-organisation of the Structural Maintenance of Chromosomes complex, MukBEF. We propose that a non-trivial feedback between the self-organising MukBEF gradient and the origins leads to accurate positioning and partitioning as an emergent property. We find excellent agreement with quantitative experimental measurements and confirm key predictions. In particular, we show that origins exhibit biased motion towards MukBEF, rather than mid-cell, consistent with the model. Overall, our findings suggest that MukBEF and origins act together as a self-organising system for chromosome segregation and introduces protein self-organisation as an important consideration for future studies of chromosome dynamics.

Proteins and multi-protein complexes play crucial roles in our cells. The function of a protein, including its interactions, is encoded in its amino-acid sequence, and the recent explosion of available sequences has inspired data-driven approaches to discover the principles of protein operation. At the root of these new approaches is the observation that amino-acid residues which possess related functional roles often evolve in a correlated way.

In the first part of my talk, I will present two novel statistical physics-inspired methods to identify which proteins are specific interaction partners, starting from sequence data alone. One method is based on the maximum-entropy inference approach that has already allowed to infer protein structures from sequences, and the other one is based on information theory.

In the second part of my talk, I will propose a physical interpretation of the "sectors" of collectively correlated amino acids that have been discovered in several protein families through statistical analyses of sequence alignments. I will show that selection acting on an additive physical property of a protein generically gives rise to a sector.

http://phi0.org/

In dimension-less theories of dynamical generation of the weak scale, the Universe can undergo a period of low-scale inflation during which all particles are massless and undergo super-cooling. This leads to a new mechanism of generation of the cosmological Dark Matter relic density: super-cooling can easily suppress the amount of Dark Matter down to the desired level. This is achieved for TeV-scale Dark Matter, if super-cooling ends when quark condensates form at the QCD phase transition. Along this scenario, the baryon asymmetry can be generated either at the phase transition or through leptogenesis. We show that the above mechanism takes place in old and new dimension-less models.

In this seminar, addressed to a broad audience, I will discuss up to what extent the question proposed in the title is not as rhetorical as it may seem.
One need only think, for example, to the fact that ordinary electromagnetism overwhelms gravity at the atomic and sub-atomic levels but on planetary scales it is the other way around.
On planetary scales, gravity must be the strongest force in order to form gravitationally bound systems.
Motivated by this simple observation, I will discuss a number of phenoemenological (motivated by the recent direct observations of gravitational waves) and theoretical (motivated by the co-called "swampland program") aspects.

The TTbar deformation is a universal irrelevant deformation of arbitrary 2d QFTs. It preserves symmetries (hence integrability when starting from an integrable theory), and energy levels on a circle obey the Burgers equation as a function of the deformation parameter. I will explain how we generalized this differential equation to antisymmetric combinations of conserved currents and/or stress-tensor: energy levels and charges also obey a hydrodynamic transport equation. We solve it for deformations of CFTs. Interestingly, the Virasoro or Kac-Moody symmetries are realized non-locally in deformed CFTs. Time-permitting I will mention supersymmetric or higher-dimensional versions.