Program
Wednesday, June 15 2022, 17:00 CET
(08:00 Los Angeles, 11:00 New York, 18.00 Istanbul, 19:00 Moscow)
Title: Dynamical RG flows and universality in classical multifield cosmological models
Speaker: Calin Iuliu Lazaroiu (Department of Theoretical Physics, IFIN-HH, Bucharest-Magurele, Romania)
Abstract: In this talk I will give a study of the scale symmetries and scale expansions in classical multifield cosmological models and their UV and IR limits, showing that these reproduce respectively the geodesic flow of the scalar manifold and a reparameterization of the gradient flow of the scalar potential on that manifold. Using the appropriate notion of IR universality classes, I show that the IR dynamics of two-field models with complete scalar field metric can be described to first nontrivial order by that of two-field models with metrics of constant Gaussian curvature. I illustrate this with results on the first order IR approximant of tame two-field models, whose scalar manifold is a hyperbolizable complete non-compact and oriented Riemann surface of finite type and whose scalar potential admits a smooth and Morse extension to the Freudenthal compactification of that surface.
The live stream recording and the presentation can be found here.
Wednesday, May 11 2022, 17:00 CET
(08:00 Los Angeles, 11:00 New York, 18.00 Istanbul, 19:00 Moscow)
Title: Some issues with gravitinos in high-scale supersymmetric models
Speaker: Emilian Dudas (CNRS, Paris)
Abstract: It has been recently realized that in some supergravity models of inflation and high-scale of supersymmetry breaking, gravitino propagation can become causal. Also, its sound speed could vanish leading to an unbounded growth in the production rate of gravitinos. I review and clarify the conditions for which this can happen. I will also comment on an infrared insight and ultraviolet origin of the potential causality.
The live stream recording and the presentation can be found here.
Wednesday, April 2022, 17:00 CET – canceled
(08:00 Los Angeles, 11:00 New York, 18.00 Istanbul, 19:00 Moscow)
Title: TBA
Speaker: Fernando Quevedo (University of Cambridge)
Abstract: TBA
Wednesday, March 16 2022, 17:00 CET
(08:00 Los Angeles, 11:00 New York, 18.00 Istanbul, 19:00 Moscow)
Title: Demystifying Black Holes
Speaker: Gia Dvali (LMU-MPI, Munich)
Abstract: Black holes are considered to be one of the most mysterious objects of nature due to their properties such as the information horizon, absence of hair, thermal evolution and information storage and processing. We argue that these properties are not specific to gravity but are generic to a large class of objects, called “saturons”, that exhibit a maximal microstate degeneracy. The role of saturons is played by solitons and various other bound states in ordinary field theories, including QCD. They exist also in non-relativistic many-body systems and can potentially be studied in labs. This view opens up a very different perspective on black hole physics, allowing its understanding in terms of the universal phenomenon of saturation. It also suggests a link with seemingly remote phenomena, such as confinement in QCD, and provides some new observational prospects.
The live stream recording can be found here.
Wednesday, February 16 2022, 17:00 CET
(08:00 Los Angeles, 11:00 New York, 18.00 Istanbul, 19:00 Moscow)
Title: Challenges in particle physics and cosmology
Speaker: Ignatios Antoniadis (LPTHE, Sorbonne Université)
Abstract: Particle physics studies the elementary constituents of matter and their fundamental forces. Very short distances are explored by particle collisions at very high energies, creating conditions similar to those governing the Universe just after the Big Bang. This is the reason that the same physics is also explored by cosmology through observations on the sky at very large distances.
The current theory of particle physics, called Standard Model, provides an accurate description of all known physical phenomena in the microcosmos. On the other hand, the Standard Model of cosmology describes very well observations, confirmed recently by the Planck satellite experiments, pointing to the existence of a new dark sector of the Universe containing dark matter and dark energy.
I will discuss the problem of scale hierarchies in particle physics and cosmology and propose ways to address it. In particular I will present a framework of obtaining inflation from supersymmetry breaking by identifying the inflaton with the superpartner of the goldstino and will describe its phenomenological consequences.
The live stream recording and the presentation can be found here.
Wednesday, January 19 2022, 17:00 CET
(08:00 Los Angeles, 11:00 New York, 18.00 Istanbul, 19:00 Moscow)
Title: Searching for Ultralight Dark Matter and Gravitational Waves with Atom Interferometers
Speaker: John Ellis (Physics Department, King’s College London & CERN)
Abstract: Following brief reviews of Dark Matter and Gravitational Waves, I will discuss atom interferometers and the prospects they offer for studying ultralight dark matter and gravitational waves in the deciHz range, focusing on the AION project in the UK and the AEDGE concept for an atom interferometer in space. These offer, in particular, the possibilities of observing the mergers of intermediate-mass black holes and a stochastic background due to a first-order phase transition in the early Universe or cosmic strings. I will also discuss the other scientific and practical opportunities in time-keeping and earth observation offered by cold atoms in space.
The live stream recording and the presentation can be found here.