Calendar

Mag
30
Mar
The black hole behind the cut (Dr Cristoforo Iossa, SISSA) @ 603 e online
Mag 30@2:00 pm–3:00 pm

Seminario di Fisica Teorica INFN/DIFI

We study holographic correlators in 2d with states whose dimensions scale with the central charge. In the 3d bulk, these heavy states create smooth horizonless solutions of supergravity that reduce to black holes in a certain limit. By solving for quadratic perturbations around these backgrounds we compute heavy-heavy-light-light four point functions at strong coupling, and study their behavior as the geometry approaches that of a black hole. We show that in this limit the spectrum of the theory becomes effectively continuous, and the correlator in momentum space develops a branch cut. The discontinuity along the cut has poles at the quasinormal frequencies of the black hole, similarly to what happens for resonances in quantum mechanics.

Per connettersi a zoom:
Topic: Theory and Pheno seminars
https://infn-it.zoom.us/j/8573185271
Meeting ID: 857 318 5271

Giu
15
Gio
Parity-odd terms in the trace anomaly of Weyl fermions: elusive or illusory? (Sebastian Franchino-Vinas, Helmholtz-Institut Dresden-Rossendorf) @ Aula 603 e online
Giu 15@2:00 pm–3:00 pm

Seminario di Fisica Teorica INFN/DIFI

There is an ongoing discussion regarding the presence of a parity-odd term in the trace anomaly of a quantum field theory consisting of a free Weyl fermion in curved spacetime. The term in question is proportional to the Pontryagin density, times an imaginary factor of dangerous astrophysical implications. In this talk, I will begin by recalling some generalities of (trace) anomalies. Afterwards, I will slowly get into the details, exposing the particularities that arise in the case of Weyl fermions. I will state the arguments provided by those who claim that the odd term does exist, as well as the replies by those of us who asseverate the opposite.

Per connettersi a zoom:
Topic: Theory and Pheno seminars
https://infn-it.zoom.us/j/8573185271
Meeting ID: 857 318 5271

Giu
21
Mer
Gluon scattering in AdS from supersymmetric localization (Pietro Ferrero – Simons Center) @ 602
Giu 21@2:00 pm–3:00 pm

Seminario di Fisica Teorica INFN/DIFI

I will discuss some of the recent progress made in the computation of holographic correlators describing the scattering of gluons in anti de Sitter space. I will focus in particular on a special AdS_5 model, arising from N D3 branes probing a D7 brane singularity, which is the holographic description of a certain 4d N=2 USp(2N) gauge theory with matter. The (mass-deformed) partition function of such gauge theory gives a non-perturbative integral constraint that the holographic correlators must satisfy, thus allowing to fix a number of coefficients that cannot be obtained from bootstrap considerations alone. Among our results: we obtain a finite coupling expression for the first higher-derivative corrections in terms of modular functions, we derive the first three orders in the small alpha’ expansion of the Veneziano amplitude in AdS_5xS^3 and we completely fix a one-loop ambiguity in the gluon amplitude without a reference to the effective action on the D7 branes, which is not known.

Set
13
Mer
EFT, positivity, and the electroweak hierarchy (Tevong You, King’s College London) @ A603 e online
Set 13@3:00 pm–5:00 pm

Seminario di Fenomenologia-

The Standard Model (SM) is an Effective Field Theory (EFT) with an electroweak hierarchy problem associated to an unnaturally light Higgs. After introducing the concept of the SM EFT and the naturalness problem, I will present the possibility that an unnatural hierarchy between certain higher-dimensional operator coefficients in a low-energy EFT would automatically imply that the Higgs’ vacuum expectation value is hierarchically smaller than the EFT cut-off, assuming the EFT emerged from a unitary, causal and local UV completion. Future colliders may have the sensitivity to infer such a pattern of coefficients for a little hierarchy with an EFT cut-off up to O(10) TeV.

Per connettersi a zoom:
Topic: Theory and Pheno seminars
https://infn-it.zoom.us/j/8573185271
Meeting ID: 857 318 5271

Ott
11
Mer
The O(N) Monolith reloaded: Sum rules and Form Factor Bootstrap @ Aula 500 e online
Ott 11@2:30 pm–3:30 pm

Seminario di Fisica Teorica (Dr. Alessandro Georgoudis, Queen Mary)

In this talk I will present the S-matrix bootstrap program and its application to the study of 2d gapped and UV complete QFTs. In our work we extend the known results from pure S-matrix bootstrap by including into the set-up form factors and spectral functions of the stress energy tensor and conserved currents. I will explain how this extended set-up works and show how the associated sum rules allow us to put bounds on quantities like the central charge of the underlying conformal theories in the UV. Based on work with L. Córdova, M. Correia and A. Vuignier.

Per connettersi a zoom
Topic: Theory and Pheno seminars
https://infn-it.zoom.us/j/8573185271
Meeting ID: 857 318 5271

Ott
18
Mer
Black hole thermodynamics from N=4 SYM: perturbations beyond supersymmetry and extremality (Alejandro Cabo Bizet, Università del Salento) @ Aula 500 e online
Ott 18@2:00 pm–3:00 pm

Seminario di Fisica Teorica-

The Bekenstein-Hawking entropy of supersymmetric and extremal (BPS) black holes has a precise statistical interpretation in the context of AdS/CFT duality. For non-BPS anti-de Sitter (AdS) black holes in dimensions larger than three, such a precise statistical interpretation has not been found yet. After reviewing the microscopic interpretation of the Bekenstein-Hawking entropy for large BPS black holes in five dimensional AdS, and time permitting, I will explain how some perturbative corrections, deviating from supersymmetry and extremality, can be computed in four-dimensional maximally supersymmetric SU(N) Yang Mills theory.

Per connettersi a zoom:
Topic: Theory and Pheno seminars
https://infn-it.zoom.us/j/8573185271
Meeting ID: 857 318 5271

Ott
20
Ven
First result of a search for diffuse supernova neutrino background in SK-Gd experiment (Dr. Masayuki Harada, Okayama University, Japan) @ Aula 605
Ott 20@11:00 am–12:00 pm

Diffuse supernova neutrino background (DSNB), which is an integrated flux of neutrinos from all past core-collapse supernovae (CCSNe), are eagerly studied in the worldwide experiment because the detection of DNSB flux makes investigation about the star formation history as well as the neutrino emission from CCSNe.

Since 2020, Super-Kamiokande (SK) detector has been updated by loading gadolinium (Gd) as a new experimental phase, “SK-Gd”. In the SK-Gd experiment, neutrons can be efficiently identified due to high cross-section and high energy gamma-ray emission of thermal neutron capture on Gd. This enables to search low-energy electron antineutrinos such as a signal of DSNB via inverse-beta decay.
Until July 2022, the observation was operated with the 0.01% Gd mass concentration, termed as SK-VI. The neutron capture fraction on Gd is about 50% at that time. In this period, we operated neutron source calibration and obtained characteristics about the neutron identification in SK-Gd detector.
Using the whole period of SK-VI, we searched for astrophysical electron antineutrinos with the energy of O(10) MeV in SK-Gd with a 22.5×552 kton·day exposure at 0.01% Gd mass concentration for a first time in SK-Gd experiment.
This seminar provides the result of the search and prospects for future observation.

Ott
25
Mer
Travels through modified gravity (Peter Dusnby, University of Cape Town) @ Aula 500 e online
Ott 25@2:30 pm–3:30 pm

Seminario di Fisica Teorica –

Over the past two decades, f(R) gravity has been at the forefront of providing an alternative to dynamical dark energy to explain the origin of late-time acceleration in the universe. This talk will provide a survey of work that has been done in this area using covariant methods, dealing with diverse topics from cosmological dynamics to gravitational lensing and perturbations of black holes.

Per connettersi a zoom:

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

Nov
8
Mer
Heavy Barions and new Interacting Boson Fermion Fermion Model results (Hugo Garcia Tecocoatzi, INFN Genova) @ Aula 500 e online
Nov 8@2:00 pm–3:00 pm

Seminario di Fisica Teorica-

In the first part of the presentation, I will present a study of the spectra and strong decay widths of heavy baryons. The masses of single heavy baryons up to the D-wave have been calculated within a constituent quark model, employing both the three-quark and quark-diquark schemes. The decay widths of the ground and excited single heavy baryons into the heavy single baryon-(vector/pseudoscalar) meson pairs and the (octet/ decuplet) baryon-
(pseudoscalar/vector) heavy meson pairs, have been calculated. Moreover, I will discuss why the presence or absence of the ρ-mode excitations in the experimental spectrum is the key to distinguishing between the quark-diquark and three-quark behaviours, as it was originally pointed out in. The quantum number assignments and predictions for mass spectra and strong-decay widths are in agreement with the available data. These findings provide valuable
guidance for future measurements in experiments as ATLAS, CMS, LHCb, Belle, and Belle II.
In the second part of this talk, I will present a new application of the Interacting Boson Fermion-Fermion Model (IBFFM) for describing double charge exchange reactions. The study of double charge exchange reactions induced by heavy ions involving candidate nuclei for neutrinoless double beta decay is a complex task carried out by the NUMEN collaboration [5], to which I belong. This investigation faces the intricacies of complex odd-odd intermediate nuclei in sequential double charge exchange processes. I will offer a comprehensive description of heavy odd-odd nuclei using the (IBFFM). Additionally, I will outline the methodology for describing transfer operators within this framework.
Finally, I will explore the potential applications of our results in future reaction codes for describing double charge exchange reactions.

Per connettersi a zoom:

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

Nov
15
Mer
Measurement-induced phase transitions in quantum circuits (Lorenzo Piroli, UNIBO, INFN BO) @ Aula 500 e online
Nov 15@2:30 pm–3:30 pm

Seminario di Fisica Teorica-

The advent of noisy-intermediate-scale quantum (NISQ) devices is opening new horizons for fundamental theoretical research. When viewed as experimental platforms for many-body quantum physics, NISQ devices can be conceptualized as systems evolving according to discrete sequences of few-body unitary processes, local projective measurements, and feedback. These ingredients give rise to new qualitative features and universal phenomena out of equilibrium, such as the recently discovered entanglement measurement-induced phase transitions (MIPTs). In the first part of the talk, I will provide an overview of the recent literature on the subject, introducing different quantum-circuit models for non-equilibrium many-body physics and the MITPs. In the second part, I will focus on some of my recent work on explicit models, showing either interesting new phenomena or allowing for analytic insight based on mappings to statistical mechanics problems.

Per connettersi a zoom:

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