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13/06/2019, 09:00
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Vincenzo Branchina (CT)13/06/2019, 09:15
Although the electroweak vacuum is not absolutely stable, when only Standard Model interactions are considered its lifetime T turns out to be much larger than the age of the Universe. However, T is extremely sensitive to the
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presence of unknown high energy new physics: the latter can enormously lower T. This poses a serious problem for the stability of our Universe. In this talk I discuss... -
Bernard Carr (Queen Mary University of London)13/06/2019, 10:10
Black holes could span 60 decades of mass - from the Planck scale (10-5g) to the cosmological scale (1022Mo) - and therefore provide an important link between microphysics and macrophysics. In the macroscopic domain, attention has recently turned to the possibility that primordial black holes (i.e. those formed in the early universe) could provide the dark matter or the black-hole mergers...
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Gabriele Gionti (Specola Vaticana)13/06/2019, 11:35
After a brief introduction to the basic ideas underlying Asymptotic Safety, we analize a RG improved Einstein-Hilbert Lagrangian in which the cosmological constant and the gravitational constant are non geometrical fields, functions of the Space-Time and determined by the Renormalization Group. The main goal of this Hamiltonian analysis is to probe the vacuum of Asymptotic Safety. This...
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Massimiliano Rinaldi (TIFP)13/06/2019, 12:05
In this talk we discuss the possibility that tensor-scalar gravity is naturally scale-invariant, at least at the classical level. This assumption has a number of phenomenological consequences on the physics of the Universe at large scale and of black holes. We consider some of these to assess whether scale-invariance is a viable and fundamental symmetry.
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Marco Celoria (GSSI and ICTP)13/06/2019, 14:30
I will review some cosmological applications of the effective field theories for condensed matter systems, characterised by the spontaneous symmetry breaking for spacetime symmetries. The associated Goldstone bosons represent the low-energy excitations, the phonons, of self-gravitating media (such as solids, fluids, superfluids and supersolids). Such an effective approach can be used to give a...
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Mariafelicia De Laurentis (Napoli University and INFN)13/06/2019, 15:30
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Luca Smaldone (Istituto Nazionale di Fisica Nucleare)13/06/2019, 17:00
We derive the Mandelstam-Tamm time-energy uncertainty relation for neutrino oscillations in a generic stationary curved spacetime. In particular, by resorting to Stodolsky covariant formula of the quantum mechanical phase, we estimate gravity effects on the neutrino energy uncertainty. Deviations from the standard Minkowski result are explicitly evaluated in Schwarzschild, Lense-Thirring and...
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Andrea Giusti (Bishop University)13/06/2019, 17:30
The turnaround radius of a large structure in an accelerating universe has been studied only for spherical structures, while real astronomical systems deviate from spherical symmetry. We show that, for small deviations from spherical symmetry, the gauge-invariant characterization of the turnaround size using the Hawking-Hayward quasi-local mass and spherical symmetry still applies, to first...
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Hristu Culetu (Ovidius University)13/06/2019, 18:00
The properties of an hyperbolically-expanding wormhole are studied. Using a particular equation of state for the fluid on the wormhole throat, we reached an equation of motion for the throat that leads to a constant surface energy density σ. The Lagrangean leading to the above equation of motion contains the ”rest mass” of the expanding particle as a potential energy. The associated...
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Giovanni Marozzi (Pisa University and INFN)14/06/2019, 09:00
In this talk, I will present the weak lensing correction, to the cosmic microwave background temperature
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and polarization anisotropies, including all the effects that go beyond the leading order. These are: post-Born corrections, LSS corrections and, for the polarization anisotropies, the correction due to the rotation of the polarization direction between the emission at the source and the... -
Alexander Kamenshchik (BO)14/06/2019, 10:00
We study static spherically and hyperbolically symmetric solutions of the Einstein equations in the presence of a conformally coupled scalar field and compare them with those in the space filled with a minimally coupled scalar field. We then study the Kantowski-Sachs cosmological solutions, which are connected with the static solutions by the duality relations. The main ingredient of these...
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Tommaso De Lorenzo (Penn State University)14/06/2019, 10:30
To obtain gravitational waveforms, results of analytical approximations for the early phase of compact binary coalescences are ‘stitched’ with –or calibrated against– numerical simulations for the late phase. Each of these calculations requires external inputs and there are additional ambiguities associated with the stitching procedure. Nonetheless, the resulting waveforms have been invaluable...
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Tereza Vardanyan (BO)14/06/2019, 11:30
We compare two different approaches to the treatment of the Wheeler-DeWitt equation and the introduction of time in quantum cosmology. One approach is based on the gauge-fixing procedure in theories with first-class constraints, while the other uses the Born-Oppenheimer method. We apply both to a very simple cosmological model and observe that they give similar predictions. We also discuss the...
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Mairi Sakelariadu (King's College London)14/06/2019, 12:00
The direct detections of Gravitational Waves (GWs) by the Advanced LIGO and Advanced Virgo interferometers have opened a new era of astronomy. Aside the current detections associated with individual loud events, one expects a superposition of coincident unresolved events leading to a stochastic GW background (SGWB). After reviewing briefly the SGWB, I will discuss how the anisotropic...
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Bruno Giacomazzo (TIFP)14/06/2019, 14:30
I will review the current state of the art of fully general
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relativistic numerical simulations of binary neutron star mergers. I will focus in particular on what we can learn from the gravitational wave and electromagnetic emission. These sources emit indeed strong gravitational waves and power bright electromagnetic signals that are strongly correlated with the properties of matter and... -
Marco Bruni (Portsmouth University)14/06/2019, 15:30
In this talk I will first describe results from cosmological simulations in the nonlinear post-Friedman approximation, a kind of post-Newtonian formalism for cosmology, showing how gravito-magnetic effects are produced by structure formation. Then I will focus on recent fully nonlinear numerical relativity simulations representing the evolution of initial perturbations in a Einstein de...
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Michele Lenzi (B)14/06/2019, 17:00
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Samuele Silveravalle (Milano University )14/06/2019, 17:30
The recent discovery of non-Schwarzschild black hole spacetimes has opened new directions of research in higher-derivative gravitational theories. However, despite intense analytical and numerical efforts, the link with the linearized theory is still poorly understood. In this work we address this point for the Einstein-Weyl Lagrangian, whose weak field limit is characterized by the standard...
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Maurizio Consoli (CT)14/06/2019, 18:00
A recent re-analysis of the ATLAS and CMS data indicates a sizeable excess of events in the 4 leptons
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channel, for a total invariant mass around 700 GeV. Its natural interpretation is in terms of a new scalar boson which decays into ZZ and then into (l+l-)(l+l-) charged final states. I will argue that this picture might have an intriguing relation with the other 125 GeV scalar particle which,... -
Giorgi Dvali (LMU and MPI, Munich and NYU)
We show that the S-matrix formulation of the theory as well as the existence of Gibbons-Hawking entropy imply that de Sitter is a state of enhanced memory storage capability and as such is a subject to memory burden effect. Unlike ordinary semi-classical information, the quantum information encoded in the state of de Sitter cannot be erased by inflation and provides a quantum cosmic hair...
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