Abstract: We review recent advances in the calculation of the two-loop Feynman integrals which contribute to five-particle scattering amplitudes with one massive leg. These amplitudes are required to provide theoretical predictions for the three-particle production (two massless and one massive particle) at the next-to-next-to leading-order approximation. We will compare several analytic approaches to the problem […]
As the LHC accumulates data, the need grows for more efficient methods to compute scattering amplitudes. One such method manages to swap the difficult problem of integrating thousands of Feynman diagrams for a much simpler one: solving a system of linear equations. This can be done when there is a known "alphabet" of appropriate singularities […]
We will present a new approach to the problem of quantising integrable systems of differential-difference equations. The main idea is to lift these systems to systems defined on free associative algebras and look for the ideals there that are stabilized by the dynamics of the lifted systems. In a reasonable class of candidate ideals, there […]
Abstract: A new approach to dark matter from the mass-radius diagram of the Universe (arxiv.org) Zoom link: https://cnrs.zoom.us/j/91049381574?pwd=TDZyU3NqT0k4MFk3cUMvc0JuOURCdz09
I will describe a new phenomenon in quantum cosmology: self-organised localisation. When the fundamental parameters of a theory are functions of a scalar field subject to large fluctuations during inflation, quantum phase transitions can act as dynamical attractors. As a result, the theory parameters are probabilistically localised around the critical value and the Universe finds […]
The Einstein Telescope (ET), a wide-band, future 3G gravitational wave detector, is to have expected detection rates of $sim 10^5 - 10^6$ BBH detections and $sim 7 times 10^4$ BNS detections in one year. The coalescence of compact binaries with total mass 20 - 100 $M_{odot}$, as typical of BH-BH or BH-NS binaries, will be […]
Abstract: Vector-Like Leptons and Inert Scalar Triplet: Lepton Flavor Violation, $g-2$ and Collider Searches (arxiv.org) Zoom link: https://cnrs.zoom.us/j/91049381574?pwd=TDZyU3NqT0k4MFk3cUMvc0JuOURCdz09
Abstract: The von Neumann entropy is key quantity in quantum information and in the investigation of many-body models. In this talk, we will show that tools from algebraic combinatorics and from the study of time and band limiting problems can simplify its computations for systems of free fermions on graphs.
Contrary to charged lepton degeneracies which are tightly constrained by the measured baryon-to-photon ratio, the allowed values of the primordial neutrino asymmetries cover a large range. In order to study the evolution of these asymmetries in the early Universe, one needs to solve a set of quantum kinetic equations that include vacuum mixing effects, mean-field […]
Abstract: https://arxiv.org/abs/2107.04601 Zoom link: https://cnrs.zoom.us/j/91049381574?pwd=TDZyU3NqT0k4MFk3cUMvc0JuOURCdz09
Classical integrable sigma-models form an important class of two-dimensional integrable field theories. It is a long standing belief that such models define renormalisable Quantum Field Theories. In this talk, I will review some recent developments related to this question. For instance, I will discuss some checks of this conjecture in several examples, including theories coupling […]