Calendar

Dic
21
Gio
Fracton gravity from spacetime dipole symmetry (Dr Alessio Caddeo, Oviedo U.) @ Aula 500 e online
Dic 21@2:30 pm–3:30 pm

Seminario di Fisica Torica

In this talk, I will present a fracton gravity gauge theory based on a covariant version of the monopole-dipole-momentum algebra. In the presence of a suitable background field, the theory includes a massive two-form and a massless symmetric two-index tensor. The latter transforms only under longitudinal diffeomorphisms, making the massless sector similar to linearized gravity, but with additional modes of lower spin. I will show that the theory can be consistently coupled to a curved background metric and discuss its possible interaction terms with itself and with matter. In addition, I will present a map between solutions of linearized gravity in Kerr-Schild form and solutions of fracton gravity coupled to matter.

Per connettersi a zoom:

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Gen
17
Mer
Positivity Constraints on Lorentz-breaking EFTs (Paolo Criminelli, ICTP) @ Aula 500 e online
Gen 17@2:30 pm–3:30 pm

Seminario di Fisica Teorica-

The coefficients of the operators of an effective field theory (EFT) are constrained to satisfy certain inequalities, under the (mild) assumption that the UV completion satisfies general requirements of causality and unitarity. We begin the extension of these ideas to theories where the Lorentz symmetry is spontaneously broken, as it happens in cosmology and condensed matter physics. Constraints are derived using dispersive arguments for the 2-point function of conserved currents and of the stress-energy tensor.

Per connettersi a zoom:

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Feb
27
Mar
Physics in Wonderland: esplorando i segreti dell’universo (Anna Marini e Bianca Bottino) @ Aula Magna DIFI
Feb 27@5:00 pm–6:30 pm

Si tratta di un evento all’interno dell’iniziativa “Un Mare di Scienza”, serie di conferenze di divulgazione scientifica organizzate dalla Scuola di Scienze Matematiche, Fisiche e Naturali.

Relatrici: Anna Marini (INFN) e Bianca Bottino (UNIGE)

I raggi cosmici sono messaggeri preziosi che ci aiutano a decifrare il nostro Universo. Attraverso la loro rivelazione possiamo captare segnali dallo spazio profondo. In questo incontro vedremo e utilizzeremo un rivelatore di raggi cosmici, partendo dai processi microscopici innescati dal passaggio dei raggi cosmici nella materia, per arrivare all’acquisizione di veri e propri segnali.

Feb
28
Mer
A History of Neutrino and its mass (Dr. Francesco Vissani LNGS Istituto Nazionale di Fisica Nucleare) @ Aula Magna
Feb 28@3:00 pm–4:00 pm

nell’ambito del workshop NuMass 2024

In this seminar, the history of the neutrino and its mass is recounted in six short chapters, with a bit of emphasis on the theoretical aspects:
1. Pauli’s proposal is presented, clarifying its significance and the context in which it arose, that of the earliest theories of the atomic nucleus.
2. The first beta-ray theory, due to Enrico Fermi, is described, clarifying its potential but also its formal and conceptual limitations.
3. Majorana’s ideas, from which the modern treatment of neutrinos and fermions in general originated, are illustrated.
4. Major advances in the next 30 years concern the existence of fermion families and the chiral structure of weak interactions, directly related to the hypothesis of neutrinos with zero mass.
5. Conceptions on the mass of neutrinos and the main ways to probe them are then summarised.
6. Prospects for development are briefly discussed in the last chapter of the story, which is the one yet to be written.

Feb
29
Gio
Odd Viscoelasticity (Prof.Piotr Surowka, Wrokaw U. of Science and Technology @ A601 e online
Feb 29@2:00 pm–3:00 pm

Seminario di Fisica Teorica

Active matter encompasses systems that are not in equilibrium, consisting of elements that either consume energy or exert work. Consequently, their macroscopic characteristics diverge significantly from those predicted by continuum field theories based on equilibrium statistical mechanics. Recent advancements in active matter research have prompted a reevaluation of the fundamental principles of materials science. This has led to the development of a novel theoretical framework known as odd(visco)elasticity. Traditional elasticity treats solids as continuous media that change shape in response to external forces. On a microscopic scale, applying force to a crystalline structure displaces its atoms, which then exert a counterforce to regain the crystal’s original configuration. However, this dynamics is fundamentally altered in active odd materials, where the response to applied forces includes not only compression or deformation but also deflection. In this presentation, I will provide an overview of the recent advancements in this field.

Per connettersi a zoom:

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Mar
6
Mer
COSMOLOGY OF THE QCD AXION: FROM THERMAL TO INFLATIONARY PRODUCTION (Alessio Notari, Universitat de Barcelona) @ Aula 501
Mar 6@2:00 pm–3:30 pm

Seminario Fisica Teorica

The axion is a hypothetical particle that could explain the absence of CP violation in QCD and has a very rich cosmological phenomenology.
In particular a population of thermally produced axions is expected to exist, in addition to a cold dark matter population. I discuss a new conservative bound on the axion mass, from production in the early universe from scattering with pions. In addition I will show that to exploit the reach of upcoming cosmological surveys, non-perturbative calculations above the QCD crossover are needed. Moreover I will also review production from other Standard Model particles (quarks, leptons).
Then, I will discuss the axion cold dark matter population, showing that its abundance depends on non-trivial evolution during primordial inflation.
Finally I will discuss the non-standard case of a heavy QCD axion, which could give rise to a detectable gravitational wave signal at Pulsar Timing Arrays or at interferometers.

Per connettersi a zoom:

https://infn-it.zoom.us/j/93341311520?pwd=RklTcFFVWjdtUzR5TUZKM3V1TjJiQT09

Mar
7
Gio
Inflationary scenario and de Sitter conjecture ( Dr Kunihito Uzawa, Kwansei Gakuin Univ. and Keio Univ.) @ Aula 605
Mar 7@2:00 pm–3:00 pm

Seminario Fisica Teorica

Several simple criteria were proposed to assess if vacua emerging from an effective scalar field theory are part of the string “landscape” or “swampland”. However, there has been little attempt to examine the swampland criterion against explicit context of kinetic terms made up of scalar fields. In this presentation, we discuss the universal behavior that in the region wherein the moduli are expected to be stable, the theory of gravity may be part of the landscape. By contrast, in the region where they may be faithful runaway potential, in the sense they possess a finite kinetic term for scalar field, the theory should thus be part of the swampland. We also consider the inflationary scenario interpolating between the cosmological landscape and the swampland and establish the part of the domain of existence where the swampland criteria are violated.

Per connettersi a zoom:

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Mar
13
Mer
Holographic match of subleading corrections to the BPS entropy of AdS5 black holes (Dr. Alejandro Ruiperez, INFN Roma 2) @ Aula 501
Mar 13@2:00 pm–3:00 pm

Seminario di Fisica Teorica

The Bekenstein-Hawking entropy of supersymmetric AdS5 black holes is matched holographically via the Legendre transform of the superconformal index on the second sheet. In this talk I shall show how this approach can be extended to account for subleading corrections to the Bekenstein-Hawking entropy, which are computed in the gravity side by adding suitable higher-derivative corrections. After reviewing the universal case studied in 2208.01007 (and 2304.06101), I will focus on ongoing work aimed to understand the case in which the black hole is charged under additional flavor symmetries.

Per connettersi a zoom:

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Mar
20
Mer
TBA (Saso Grozdanov, Edimburgh)
Mar 20@2:00 pm–3:00 pm
Mar
27
Mer
TBA (Ilaria Brivio, Bologna)
Mar 27@2:00 pm–3:00 pm