Quantum Field Theory Center – QTC

Speaker: Giulia Muco, PhD student at QTC, who is going to talk about CFT and Large Charge Expansion. Here below you can find an abstract of the talk and the related reference.Abstract: Using the large-charge expansion, we prove a necessary condition for a CFT to exhibit conformal symmetry breaking, under the assumption that a continuous global symmetry is also broken on the moduli space: there must be a tower of charged local operators whose scaling dimensions are asymptotically linear in the charge. In supersymmetric theories with a continuous R-symmetry and a holomorphic moduli space, the existence of such a tower of operators follows trivially from a BPS condition: their scaling dimensions are then exactly linear in the R-charge. We illustrate the more general statement in several examples of three-dimensional N=1 CFTs, where the leading linear behavior receives nontrivial corrections. By considering a suitable scaling limit, we also relate the spectrum of states with large charge on the cylinder (isomorphic to local operators) to the spectrum of massive particles on the moduli space.Related reference: [download link]Location: The DIAS Meetingroom Nord (V24-410-2)You can also join via Zoom (passcode: 060379).The event is open to all.

Speaker: Vigilante Di Risi, PhD studentAbstract: A discussion of the paper “Higher Flavor Symmetries in the Standard Model”.Location: The DIAS Meetingroom Syd (V22-503a-2)You can also join via Zoom (passcode: 060379).The event is open to all.

Speaker: Vigilante Di Risi, PhD studentAbstract: An introduction to Higher Symmetries.Location: The DIAS Meetingroom Syd (V22-503a-2)You can also join via Zoom (passcode: 060379).The event is open to all.

Speakers: Alessandra D’Alise and Clelia Gambardella, PhD studentsAbstract: An introduction to 2-colour QCD.Location: The DIAS Meetingroom Syd (V22-503a-2)You can also join via Zoom (passcode: 060379).The event is open to all.

Speakers: Alessandra D’Alise and Clelia Gambardella, PhD studentsAbstract: An introduction to 2-colour QCD.Location: The DIAS Meetingroom Syd (V22-503a-2)You can also join via Zoom (passcode: 060379).The event is open to all.

Speakers: Alessandra D’Alise and Clelia Gambardella, PhD studentsAbstract: An introduction to 2-colour QCD.Location: The DIAS Meetingroom Syd (V22-503a-2)You can also join via Zoom (passcode: 060379).The event is open to all.

Speaker: Marika D’Avanzo, PhD studentAbstract: Introduction to to Animal Viruses.Location: The DIAS Meetingroom Syd (V22-503a-2)You can also join via Zoom (passcode: 060379).The event is open to all.

Speaker: Marika D’Avanzo, PhD studentAbstract: Virus Transmission and Epidemiology.Location: The DIAS Meetingroom Syd (V22-503a-2)You can also join via Zoom (passcode: 060379).The event is open to all.

Speaker: Sven Bjarke Gudnason, Professor Abstract: Baryons from holographic instantons.Location: The DIAS Meetingroom Syd (V22-503a-2)You can also join via Zoom (passcode: 060379).The event is open to all.

Speaker: Devon Stockall, PhD studentAbstract: Conformal Field Theories and Category Theory.Location: The DIAS Meetingroom Syd (V22-503a-2)You can also join via Zoom (passcode: 060379).The event is open to all.

Speaker: Emmanuele Battista, PostdocAbstract: Post-Newtonian Generation of Gravitational Waves in Einstein-Cartan theory.Location: The DIAS Meetingroom Syd (V22-503a-2)You can also join via Zoom (passcode: 060379).The event is open to all.

Speaker: Antonio Iovino, master studentAbstract: The recent data releases by multiple pulsar timing array (PTA) experiments show evidence for Hellings-Downs angular correlations indicating that the observed stochastic common spectrum can be interpreted as a stochastic gravitational wave background. We study whether the signal may originate from gravitational waves induced by high-amplitude primordial curvature perturbations. Such large perturbations may be accompanied by the generation of a sizeable primordial black hole (PBH) abundance. We discuss in which scenarios the inclusion of non-Gaussianities in the computation of the abundance can lead to a signal compatible with the PTA experiments without overproducing PBHs. Eventually we briefly discuss other astrophysical and cosmological explanations for the PTA data.Location: The DIAS Meetingroom Syd (V22-503a-2)You can also join via Zoom (passcode: 060379).The event is open to all.

Speaker: Manuel Del Piano, PhD studentAbstract: In the realm of quantum gravity theories, predictions suggest deviations from classical black hole solutions. One promising avenue for exploring these deviations is through a model-independent approach that utilizes metric deformations parameterized by physical quantities like proper distance. While this approach preserves the space-time's invariance under coordinate transformations, practical computations are daunting due to the dependence of distance on the deformed metric. Our study focuses on spherically symmetric and static metrics, aiming to establish a self-consistent framework for computing the distance function near black hole event horizons. We achieve this by introducing a minimal level of regularity at the horizon, allowing us to derive explicit (series) expansions of the metric. This advancement enables us to calculate essential thermodynamic quantities, such as the Hawking temperature and entropy, using model-independent expressions that extend beyond the limitations of large mass expansions. Moreover, we investigate the implications of imposing conditions like the absence of curvature singularities at the event horizon. Surprisingly, we uncover violations of these conditions in certain existing models, highlighting the need for further refinement and exploration in the field of quantum gravity and black hole physics.Location: The DIAS Meetingroom Syd (V22-503a-2)You can also join via Zoom (passcode: 060379).The event is open to all.

Speaker: Pietro ButtiAbstract: Neural network quantum states (NNQS) represent a novel approach in quantum many-body physics using techniques inspired by artificial neural networks combined with standard variational Monte-Carlo methods. The growing computational and algorithmic capabilities make this method comparable to standard state-of-the-art methodologies while offering promising advantages. It can leverage extensive research in machine learning and easily integrate with existing libraries, simplifying code development in an unprecedented way. This accessibility and versatility make it appealing for developing new applications, even beyond quantum many-body physics itself. The purpose of this talk is to provide a thorough introduction of the topic with the help of some practical example.Location: The DIAS Meetingroom Syd (V22-503a-2)You can also join via Zoom (passcode: 060379).The event is open to all.

Discussion of the paper Exact evaluation of large-charge correlation functions in non-relativistic conformal field theory by S. R. Beane, D. Orlando, and S. Reffert. Speakers: Vigilante Di Risi and Davide Iacobacci, PhD students   • Download slides from the talkAnd discussion of the paper Two-index SU(N) theories QCD, Orientifolds, Super Yang-Mills, Lattice and Steven Weinberg’s ππ scattering legacy by F. Sannino.Speakers: Sofie Martins and Mattia Damia Paciarini, PhD students   • Download slides from the talkLocation: The DIAS Meetingroom Syd (V22-503a-2)You can also join via Zoom (passcode: 060379).The event is open to all.

Speaker: Stefan Hohenegger, Senior ResearcherAbstract: In this talk I introduce basic concepts in information theory and apply them to epidemiology and population dynamics: I start by reformulating simple evolution models in terms of probability distributions. This allows me to construct the Fisher information, which I interpret as the metric of a one-dimensional differentiable manifold. For systems that can be effectively described by a single degree of freedom, I show that their time evolution is fully captured by this metric. In this way, I extract universal features across seemingly very different models. This further motivates a reorganisation of the dynamics around zeroes of the Fisher metric, corresponding to extrema of the probability distribution. Concretely, I propose a simple form of the metric for which I analytically solve the dynamics of the system that well approximates the time evolution of various established models in epidemiology and population dynamics, thus providing a unifying framework.Location: The DIAS Meetingroom Syd (V22-503a-2)You can also join via Zoom (passcode: 060379).The event is open to all.

Speaker: Michele della Morte, Associate ProfessorAbstract: Michele della Morte will discuss “A first look at Quantum Computing” based on Professor Nathaniel David Mermin’s book Quantum Computer Science – An Introduction.In particular, Michele will introduce basic concepts in Quantum Computing and discuss the example of the Feynman Deutsch problem. Location: The DIAS Meetingroom Syd (V22-503a-2)You can also join via Zoom (passcode: 060379).The event is open to all.

Speaker: Francesco Sannino, Professor Abstract: I will first provide a mathematical classification of the various extensions of the Standard Model according to their degree of naturality.I will then argue in favour of the existence of a dual description of the Standard Model in terms of “electric” variables, an idea inspired by Dirac electromagnetic-duality idea and the work by Seiberg for gauge-gauge duality in supersymmetric QFTs.I will finally introduce a toy  Standard Model to elucidate the crucial aspects about duality which, as I will show, can provide elegant solutions to outstanding problems such as why we have three generations and why the Standard Model could be a natural theory in plain sight.  Location: The DIAS Meetingroom Syd (V22-503a-2)You can also join via Zoom (passcode: 060379).The event is open to all.

Speaker: Claudio Pica, ProfessorAbstract: TBALocation: The DIAS Meetingroom Syd (V22-503a-2)You can also join via Zoom (passcode: 060379).The event is open to all.

Speaker: Emmanuele Battista, PostdocAbstract: In this seminar, we investigate a Schwarzschild metric whose signature changes upon crossing the event horizon. In particular, when r > 2M the metric has the usual Lorentzian signature; then, at r = 2M it becomes degenerate, and when r < 2M  it attains the ultrahyperbolic signature. In this scenario, the time variable is real-valued outside the event horizon and becomes imaginary inside it. This geometry gives rise to what we term a Lorentzian-Euclidean black hole. The underlying Riemann tensor exhibits Dirac-delta-like singularities which we regularize by employing the Hadamard partie finie technique. In this way, we demonstrate that the Lorentzian-Euclidean metric represents a solution of the vacuum Einstein equations. The analysis of the motion of radially moving observers reveals that the black-hole singularity can be avoided. The seminar is based on ArXiv: 2404.17267. Location: The DIAS Meetingroom Syd (V22-503a-2)You can also join via Zoom (passcode: 060379).The event is open to all.

Speaker: Giuseppe Fabiano, PhD studentAbstract: Several heuristic arguments in quantum gravity research suggest that there should be a fundamental limit to localization of physical systems. If this argument is to be taken at face value, the classical notion of smooth spacetime should be replaced by that of a "quantized" spacetime. A suitable framework for describing such a scenario is that of non-commutative geometry, where coordinate functions on a manifold are promoted to non-commutative operators. In my presentation, I will highlight some theoretical aspects regarding the "quantum symmetries" of noncommutative spacetimes and I will discuss some phenomenological opportunities arising from relativistic toy models inspired by spacetime noncommutativity.Location: The DIAS Meetingroom Syd (V22-503a-2)You can also join via Zoom (passcode: 060379).The event is open to all.

Speaker: Davide Iacobacci, PhD student at SSM, Naples, who is going to talk about Entanglement Entropy in the framework of AdS-CFT correspondence.Abstract: We delve into the interplay between quantum information theory and gravitational physics, focusing on the Ryu-Takayanagi (RT) formula within the framework of the AdS/CFT correspondence. We begin with a historical overview of holography, tracing key developments from 't Hooft and Susskind's early insights to Maldacena's AdS/CFT duality. The core of the presentation explores entanglement entropy, providing an intuitive understanding and highlighting its significance in quantum field theory (QFT) and many-body systems. We then introduce the RT formula, illustrating its role in linking entanglement entropy to minimal surfaces in anti-de Sitter (AdS) space. Through concrete examples, including the AdS3/CFT2 correspondence and black hole cases, we demonstrate the practical calculations and implications of this relationship. The presentation concludes by emphasising the broader impact of these concepts, underscoring the essential role of entanglement in understanding quantum phenomena. We end with a new quantum information theoretic view for studying gravitational back-reaction. Location: The DIAS Meetingroom Syd (V22-503a-2)You can also join via Zoom (passcode: 060379).The event is open to all.

Speaker: Domenico Frattulillo, who is part of our research unit and has completed his PhD recently. He is going to talk about phenomenology in quantum gravity.Abstract: Over the last 20 years there has been considerable interest in the possibility of quantum-gravity induced in-vacuo dispersion, namely the possibility that spacetime itself might behave like a dispersive medium for particle propagation.The way in which in-vacuo dispersion produces redshift-dependent corrections to the time of flight of astrophysics particles depends on the model-dependent interplay between Planck-scale effects and spacetime curvature/expansion. I present the most general formula for the leading order redshift-dependent correction to the time of flight for the scenario in which relativistic symmetries are deformed at the Planck scale (DSR).Finally, in the second part of the talk, I present how it is possible to test in-vacuo dispersion through Gamma ray bursts data. In fact, observations of GRBs, which in general have high redshift distances and emit (nearly-)simultaneously photons of different energies and (probably) neutrinos, could be well suited for finding a manifestation of this novel energy dependence of the speed.Location: The DIAS Meetingroom Syd (V22-503a-2)You can also join via Zoom (passcode: 060379).The event is open to all.

Speaker: Giacomo Cacciapaglia, who is part of our research unit and is currently working in Lyon. The talk is about measuring Hawking radiation from tiny black holes, which may be formed after astrophysical black holes mergers. Here below you can find the abstract of the talk.Abstract: We show that it is possible to observe the Hawking radiation emitted by small black holes assumed to form in catastrophic astrophysical events such as black hole mergers. Gamma ray bursts in the TeV range are unique footprints of these asteroid-mass black hole morsels ejected during the merger. The time delay of the gamma ray bursts from the gravitational wave event is correlated to the mass distribution of the morsels. The integrated mass of the morsels allowed by the unaccounted merger mass leads to a Hawking induced radiation in photons that is above the sensitivity of atmospheric Cherenkov telescopes such as HESS, LHAASO and HAWC.Location: The DIAS Meetingroom Syd (V22-503a-2)You can also join via Zoom (passcode: 060379).The event is open to all.

Speaker: Vania Vellucci, PhD student at SISSA. She has been working mainly on Black Holes physics, and her talk will focus on the study of Black Holes singularities. Here below you can find more information.Abstract: In a complete theory of gravity we expect space-time singularities to be regularized by quantum effects. From this point of view, we have two possible regular alternatives to singular black holes (BHs) to describe the ultracompact objects that we saw in our universe: regular black holes and horizonless compact objects. I will talk about the possible structures of these black hole mimickers and the gravitational waves ringdown signal that we expect from their coalescence. Location: The DIAS Meetingroom Syd (V22-503a-2)You can also join via Zoom (passcode: 060379).The event is open to all.

Speaker: Davide IacobacciAbstract:Effective Field Theories (EFTs) are powerful tools for exploring New Physics beyond the Standard Model in a model-independent framework. In this talk, we first revisit the general framework of EFTs, illustrating their application within the Standard Model. We then apply the Weak Effective Theory to investigate the current status of B meson anomalies. Specifically, we re-examine recent measurements of R_K​ and R_{K^*}​, now in agreement with Standard Model predictions, alongside results for the process BR(Bs→μ+μ−) and earlier determinations of R_{D^*}​ and BR(Bc→τν). Through this analysis, we derive analytic constraints on the associated Wilson coefficients in both the b→s and b→c transitions. These constraints are used to select leptoquark models and to provide an estimate of the potential New Physics scale.Location: The DIAS Meetingroom Syd (V22-503a-2)You can also join via Zoom (passcode: 060379).The event is open to all.

Speaker: Lorenzo Iacobacci, Postdoc at Brussel UniversityAbstract: We will explore the connection between Celestial and Euclidean Anti-de Sitter (EAdS) holography in the massive scalar case. Specifically, exploiting the so-called hyperbolic foliation of Minkowski space-time, we will show that each contribution to massive Celestial correlators can be reformulated as a linear combination of contributions to corresponding massive Witten correlators in EAdS. This result will be demonstrated explicitly for contact diagrams, and it extends to all orders in perturbation theory by leveraging the bootstrapping properties of CFTs.Location: The DIAS Meetingroom Syd (V22-503a-2)You can also join via Zoom (passcode: 060379).The event is open to all.

Speaker: Manuel Del Piano, PhD student at Scuola Superiore Meridionale (SSM)Abstract: In this presentation, we discuss how recent advances in black hole physics can inform our understanding of Hawking radiation from astrophysical events. By leveraging the large D limit of General Relativity, we gain a simplified yet powerful framework to describe higher-dimensional black hole dynamics. Additionally, insights into the instability of ultra-spinning black holes open up possibilities for new, exotic black hole configurations. These theoretical tools are instrumental in refining predictions for the detection of Hawking radiation from black hole mergers.  References: http://arxiv.org/abs/1302.6382http://arxiv.org/abs/hep-th/0308056Location: The DIAS Meetingroom Nord (V24-410-2)You can also join via Zoom (passcode: 060379).The event is open to all.

Speaker: Marika D’Avanzo, PhD student at Federico II (Napoli University, Italy). She works on epidemiology, and her talk will be about early detection and dynamics of COVID-19 variants. More details below.Abstract: In this presentation, we will explore a novel approach to analyse the evolution and spread of SARS-CoV-2 variants across different countries using genomic sequencing data. By employing an unsupervised clustering algorithm, we are able to identify chains of variants and fit their temporal dynamics using a sigmoid function. The study provides insights into key parameters, such as the time from the first case and the reaction time, which can serve as early indicators for new variant detection. Furthermore, we introduce a calibration curve to estimate t_0 based on the number of sequences available per week, offering a practical framework for future surveillance efforts. The results also highlight the ability to differentiate between stable and non-stable variant chains within a few weeks of detection, potentially providing a low-cost early warning system for emerging variants. Location: The DIAS Meetingroom Nord (V24-410-2)You can also join via Zoom (passcode: 060379).The event is open to all.

Speaker: Sofie Antonia Martins, PhD studentAbstract: Composite Higgs theories are a class of theories that replace the weak sector with an underlying strongly coupled sector, solving the Hierarchy problem. In this context, lattice gauge theory is useful for providing phenomenological predictions for Composite Higgs theories because it can capture non-perturbative dynamics. In this talk, I want to give an overview of how to use lattice gauge theory for providing non-perturbative phenomenological results and show such results for an SU(2) gauge theory with two flavors in the fundamental representation. We chose this model because, in terms of the number of colors and flavors, this model is the minimal candidate that preserves a custodial symmetry necessary to fix the rho-parameter in the replaced weak sector.Literature:https://pos.sissa.it/453/094https://pos.sissa.it/451/035https://www.sciencedirect.com/science/article/pii/S0370157320302519?via%3DihubLocation: The DIAS Meetingroom Nord (V24-410-2)You can also join via Zoom (passcode: 060379).The event is open to all.

Speaker: Alessandra D’Alise, PhD studentAbstract: Recent pandemics triggered the development of a number of mathematical models and computational tools apt at curbing the socio-economic impact of these and future pandemics. The need to acquire solid estimates from the  data  led to the introduction of effective approaches such as  the epidemiological Renormalization Group (eRG). A recognized relevant factor impacting the evolution of pandemics is the feedback stemming from individuals' choices. The latter can be taken into account via the information index which accommodates the information-induced perception regarding the status of the disease and the memory of past spread. We, therefore, show how to augment the eRG by means of  the information index.  We first develop  the behavioural  version of the eRG  and then test it against the US vaccination campaign for COVID-19. We find that the behavioural augmented eRG improves the description of the pandemic dynamics of the US divisions for which the epidemic peak occurs after the start of the vaccination campaign. Our results strengthen the relevance of taking into account the human behaviour component when modelling pandemic evolution. To inform public health policies, the model can be readily employed to investigate the socio-epidemiological dynamics, including vaccination campaigns, for other regions of the world.Reference: arXiv:2407.20711v1Location: The DIAS Meetingroom Syd (V22-503a-2)You can also join via Zoom (passcode: 060379).The event is open to all.

Speaker: Vigilante Di Risi, PhD student at Federico II University of Naples. In his talk, Vigilante will tell us about QCD and dual theories. More on this below.Abstract: In the late nineties, in a series of exceptional papers, Seiberg provided strong support for the existence of a consistent picture of an electric-magnetic duality within a supersymmetric framework. One of the most relevant of Seiberg’s results has been the identification of the boundary of the conformal window for supersymmetric QCD as function of the number of flavours and colours. Generalizing Seiberg's ideas to non-supersymmetric QCD it is possible to recover analytical results on the extension of the QCD conformal window. By means of  't Hooft anomaly matching, magnetic duals of QCD can be built and some aspects of the QCD non-perturbative regime can be trustably discussed. The agreement with analogous computations (e.g. lattice QCD, all-orders beta function, ladder approximation) has been shown to be excellent. References:arXiv:0907.1364v3arXiv:hep-th/9706074v3arXiv:1101.1522v1arXiv:0909.4584v1Location: The DIAS Meetingroom Syd (V22-503a-2)You can also join via Zoom (passcode: 060379).The event is open to all.

Speaker: This week’s JC will be split in two parts. In the first, Vigilante Di Risi will finish his talk from last time.Then, our next speaker will be Giacomo Cacciapaglia from the Université of Lyon, France. More on his talk below.Abstract: Current data does not allow to uniqueli determine the nature of the Higgs boson. Could it be the product of a composite sector at the electroweak scale? I will discuss how current and future collider programmes can lead to the discovery or exclusion of this broad scenario. Cross study of various sectors of the theory are crucial in this task.Location: The DIAS Meetingroom Nord (V24-410-2)You can also join via Zoom (passcode: 060379).The event is open to all.