Séminaire

Chaotic behavior in field and string theory

My talk will be divided into two parts: In the first I will present a novel
measure of chaotic scattering amplitudes.  For chaotic scattering the distribution function is given
by the β-ensemble of random matrix theory (RMT). We show that amplitudes of one highly
excited string (HES) state with two or three scalars in open bosonic string theory admit
this behavior. Quite remarkably this measure applies also to the distributin of non-trivial
zeros of the  Riemann zeta function.

High Scale Leptogenesis and Low Energy CP Violation

Aspects of non-resonant high scale leptogenesis (LG) associated with type I seesaw mechanism  will be discussed.
The questions of
i) how low can be the LG scale in the case of three right-handed neutrinos,
ii) how low/high can be the LG scale when the  CP violation is provided by the Dirac or Majorana phases in the PMNS neutrino mixing matrix,
iii)   how the transitions between the different flavour regimes take place, and

Euclidean Wormholes and Holography

In this talk I will review the physics of Euclidean wormholes in a holographic context. By studying the properties of various observables on these Euclidean backgrounds holographically, we found the common behaviour that there are interactions between the quantum field theories that live on each of the wormholes' boundaries. These interactions are very weak in the UV and become strong in the IR.

Galaxies, binaries and gravitational waves

Abstract
========
We are now routinely detecting gravitational waves (GW) emitted by
merging black holes and neutron stars. Those are the afterlives of
massive stars that formed all across the Universe - at different times
and with different metallicities.
Birth metallicity plays an important role in the evolution of massive
stars.
Consequently, the population properties of mergers are sensitive to the
metallicity dependent cosmic star formation history (fSFR(Z,z)).

The Oxford Handbook of the History of Quantum Interpretations

In the same spirit as The Oxford handbook of the history of Quantum Interpretations, the two days offer a historical overview of the contrasts that have been at the heart of quantum physics over the past 100 years. Drawing on the extensive expertise of several lecturers working in the fields of physics, history and philosophy.
Thus, the objective of these two days is to fuel the ongoing debate on the foundations of quantum mechanics by dealing with the major open questions concerning the interpretations of Quantum Mechanics.

Primordial black holes from supercooled first-order phase transition

Cosmological first-order phase transitions are said to be strongly supercooled when the nucleation temperature is much smaller than the critical temperature. They are typical of potentials which feature nearly scale-invariance, for which the bounce action decreases only logarithmically with time. The phase transition takes place slowly and the probability distribution of bubble nucleation time is maximally spread. Hubble patches which get percolated later than the average are hotter than the background after reheating and potentially collapse into black holes.

Soft theorems for boosts and other time symmetries

I will derive new classes of soft theorems for theories in which time symmetries (i.e., symmetries that involve the transformation of time, an example of which are Lorentz boosts) are spontaneously broken. The soft theorems involve unequal-time correlation functions with the insertion of a soft Goldstone in the far past. I will discuss explicit examples, which include the effective theory of a relativistic superfluid and inflationary cosmology.

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