ABSTRACT:
The era of precise observations in modern cosmology has led to a deeper understanding of the content and dynamics of the universe. However, current tensions in the determination of key cosmological parameters between late and early observations may indicate gaps in our understanding of Physics. In addition to the well-known tensions over the expansion rate and the rate of matter clustering, another tension is slowly building up between cosmology and local experiments over the neutrino mass constraints. Mass-varying neutrino models, in which neutrinos interact with dark energy, have the potential to relax this tension

ABSTRACT:

In this talk my purpose is to describe how excited vortices from non excited BPS in the Abelian Higgs
model scatter in a far more complex manner than in the geodesic approach over the BPS moduli space.
I will concentrate in the N=2 magnetic flux case where a fractal structure showing a different number
of vortices at different windows in the initial velocity arises. The conceptual framework where this chaotic
structure emerges is based on the collective coordinates effective dynamics. The outcome will be compared
with the results offered by the numerical analysis performed by Morgan Rees in the full AHM. Time permitting
I will sketch preliminary ideas about the existence of similar structures in the system of N=3 excited vortices.

Abstract: First order phase transitions are ubiquitous in nature,
however, this notion is ambiguous and highly debated in the case of
open quantum systems. We present a paradigmatic example which allows
for elucidating the key concepts. We show that atoms in an optical
cavity can manifest a first-order dissipative phase transition where
the stable co-existing phases are quantum states with high quantum
purity. These states include atomic hyperfine ground states and
coherent states of electromagnetic field modes. We present the
experimental demonstration of characteristic features of a quantum
bistability, including the enhanced quantum fluctuations during the
phase transition and hysteresis in the order parameter.

Looking for Carroll particles in the two-time spacetime.

SPEAKER: Alexander Kamenshchik (Univ. of Bologna)

ABSTRACT:
We make an attempt to describe Carroll particles with a non-vanishing value of energy (i.e. the Carroll
particles which always stay in rest) in the framework of two time physics, developed in the series of papers
by I. Bars and his co-authors. In the spacetime with one additional time dimension and one additional space
dimension one can localize the symmetry which exists between generalized coordinate and their conjugate
momenta. Such a localization implies the introduction of the gauge fields, which in turn implies the appearance
of some first-class constraints. Choosing different gauge-fixing conditions and solving the constraints one obtain
different time parameters, Hamiltonians, and generally, physical systems in the standard one time spacetime.
In this way such systems as non-relativistic particle, relativistic particles, hydrogen atoms and harmonic oscillators
were described as dual systems in the framework of the two time physics. Here, we find a set of gauge fixing
conditions which provides as with such a parametrization of the phase space variables in the two time world
which gives the description of Carroll particle in the one time world. Besides, we construct the quantum theory
of such a particle using an unexpected correspondence between our parametrization and that obtained by Bars
for the hydrogen atom in 1999.

ABSTRACT:
Since their proposal, Lorentz violating theories of gravity have posed a potential threat to black hole thermodynamics, as superluminal signals
appeared to be incompatible with the very black hole notion. Remarkably, it was soon realized that, in such theories, causally disconnected r
egions of space-time can still exist thanks to the presence of universal horizons: causal barriers for signals of arbitrary high speed. Several
investigations, sometimes with contrasting results, have been performed to determine if these horizons can be associated with healthy
thermodynamic properties similar to those associated with Killing horizons in General Relativity.
In this talk, I will show that: 1) there is a thermal, and most of all species-independent, emission associated to universal horizons, determined
by their surface gravity; 2) due to the modified dispersion relation of the matter fields, the low energy part of the emitted spectrum is affected
by the presence of the Killing horizon, in a way similar to an effective refractive index, leading at low energies (w.r.t. the Lorentz breaking
scale) to an emission that mimics a standard Hawking spectrum (i.e. one determined by the Killing horizon surface gravity); 3) the whole picture
is compatible with a globally well defined vacuum state i.e. an Unruh state associated with preferred observers, which however at very low
energies it is basically indistinguishable from the standard Unruh vacuum associated to metric free-falling observers. One can then conclude
that Hawking radiation is remarkably resilient even within the context of gravitational theories entailing the breakdown of local Lorentz invariance