Bounding parameters in the web of swampland conjectures

The swampland program provides criteria to identify consistent low energy effective theories of quantum gravity. However, at present most of these criteria are at the state of conjectures and depend on unspecified order one parameters. In this talk, I will review some of these conjectures and suggest possible relationships among them. As a byproduct of this analysis, one can propose bounds for the parameters and make the associated conjectures suitable for falsification.

The physics of the nucleus of cells

The nucleus of cells is a complex system comprising tens of long linear biopolymers, the chromosomes, together with a large number of different molecules and aggregates, as proteins and nuclear bodies, interacting with each other at multiple space and time scales. Chromosomes architecture and their interaction network are involved in vital cell functions, controlling gene expression, whereas abnormal chromosome folding has been related to severe human diseases. In this talk, I discuss how massive data on genome architecture, generated thanks to significant experimental advances in the last decade, can be explained in a principled approach based on the Statistical Mechanics of polymers and some of their underlying molecular mechanisms understood 1,2. I next show that the effects of pathogenic genomic mutations can be predicted by physics models, as validated by experimental data, opening the way to revolutionary applications in biomedicine 3,4.

Center Symmetry Realization in Trace Deformed Yang-Mills Theory

In this talk I will show recent lattice results obtained in the trace deformed Yang-Mills (YM) theory. It is known that YM theory defined on a space with one or more compactified dimensions undergoes a phase transition which separates the confined, non perturbative, phase from the deconfined, perturbative one. The trace deformation consists of an additional piece added to the standard YM action, which preserves the realization of center symmetry also in the limit of vanishing compactification length. With the deformation it is therefore possible to have a "reconfined" phase also at values of the compactification length much smaller than the critical one, at which the transition occurs. The reconfined phase shows interesting properties such as volume independence and it could give information on how the non-perturbative properties, for example the topology or the localization properties of the Dirac operator spectrum are related to the realization of center symmetry.

N=2, conformal theories gauge theories at large R-charge: the SU(N) case

Recently Grassi, Komargodski and Tizzano showed that the large R-charge limit of extremal correlators of Coulomb branch operators in N=2 superconformal SQCD with gauge group SU(N) is captured by a chiral matrix model of Wishart-Laguerre type. We show that such a description is a feature of all SU(N) superconformal gauge theories with N=2 supersymmetry and it allows us to efficiently obtain perturbative results to a high order in a 't Hooft like double scaling limit. We also cross check these results using Feynman diagrams and find that in this limit, at each order only those diagrams contribute that maximize the genus. Remarkably such a matrix model also emerges as the large charge limit of one point functions of chiral operators in the presence of Wilson loop. The resulting perturbative series can be resummed to obtain a remarkably simple expression which affords us an interesting view of the mass spectrum of heavy BPS states.

Exact results with defects

I will give a summary of recent progress in the computation of exact results in the presence of superconformal defects, focusing on a special class of defect correlators involving the displacement operator and its superpartners.

B -> D* form factors and Vcb extractions

The determination of form factors for the process $B\to D^{(*)}$ is of great importance given recent anomalies in semileptonic $B$ decays and the discrepancy between the inclusive and exclusive determination of $|V_{cb}|$. I present a recent analysis carried out in the framework of Heavy-Quark Expansion, where for the first time all the contributions to order the order $\order{\alpha_s, 1/m_b, 1/m_c^2}$ are included. Thanks to new predictions for the full set of form factors from Light-Cone Sum Rules methods for the whole set of $B_q \to D_q^{(*)}$ form factors with $q=u,d,s$, it is possible to go beyond the commonly used $SU(3)_F$ symmetry. This affects especially the unitarity constraints, which are imposed throughout the analysis. I discuss the phenomenological impact of this parametrisation, with emphasis on predictions for various observables and the extracted value of $V_{cb}$. Furthermore, I discuss the saturation of the unitarity bounds and the validity of $SU(3)_F$ symmetry.

Gravitational wave signatures of exotic compact objects

Gravitational waves from the coalescence of compact binaries provide a unique opportunity to test gravity in strong field regime. In particular, the postmerger phase of the gravitational signal is a proxy for the nature of the remnant. Some quantum-gravity models predict the existence of horizonless compact objects which overcome several semi-classical issues associated to black holes. Such exotic compact objects emit gravitational wave echoes in the postmerger phase as characteristic fingerprints. In this talk, I investigate the viability of spinning exotic compact objects with a reflective surface. I show that a surface absorption of 60% ensures the stability of the geometries for any spin. Finally, I provide a gravitational-wave template for the postmerger signal and the echoes of the compact object. The template can easily be implemented to perform a matched-filter based search for echoes in current and future gravitational wave data.

Feynman Integrals reduction and Intersection Theory

The reduction of a large number of scalar multi-loop integrals to a smaller set of Master Integrals is an integral part of the computation of any multi-loop amplitudes. Such reduction is usually achieved by solving huge systems of linear relations existing among Feynman integrals. Here we present a new way to obtain such reduction, where intersection numbers are used to project Feynman integrals directly on the set of Master Integrals, acting as a scalar product between them. Moreover we present a general algorithm for constructing multivariate intersection numbers relevant to Feynman integrals. We apply it to the derivation of contiguity relations for special functions and to the decomposition of a few Feynman integrals at one- and two-loops, as first steps towards potential applications to generic multi-loop integrals.

Alpha'-corrections to integrable deformations

The "homogeneous Yang-Baxter deformation" is a useful technique to generate integrable deformations of two-dimensional sigma-models. The fact that it is also a solution-generating technique in supergravity recently motivated a lot of research also in that direction. In this talk I will outline how to derive the alpha'-corrections (i.e. corrections in the inverse string tension) to Yang-Baxter deformed backgrounds using the formalism of Double Field Theory. This result puts Yang-Baxter deformations on firmer ground in string theory beyond the supergravity approximation, and it also indicates how to obtain similar results for non-abelian T-duality, another important solution-generating technique.

Cosmic discordances

The Cosmic Microwave Background (CMB) temperature and polarization anisotropy measurements from the Planck mission have provided strong confirmation of the LCDM model of structure formation. However, there are a few interesting tensions with other cosmological probes and anomalies in the data that leave the door open to possible extensions to LCDM. The most famous ones are the Hubble constant and the S8 parameter tensions, the Alens anomaly and a curvature of the Universe. I will review all of them, showing some interesting extended cosmological scenarios, in order to find a new concordance model that could explain the current cosmological data.

Polarized Weak Bosons at the LHC

Isolating the polarization modes of massive electroweak bosons (W/Z) provides a crucial probe for the gauge and Higgs sectors of the Standard Model (SM) of fundamental interactions. Furthermore, it represents a source of discriminating power between the SM and new physics models. The Run 2 dataset and the foreseen luminosities of the next LHC runs will enable polarization measurement in multi-boson processes. Therefore a more complete theoretical understanding is needed for the description of such processes. After recalling the main issues that arise when separating polarizations at the amplitude level, I will present some recent developments in the Monte Carlo description of polarized bosons (up to NLO accuracy) together with a selection of phenomenological results at the LHC. Special focus will be dedicated to boson pair production and vector boson scattering, in the fully leptonic decay channel.

On Vacuum Stability without Supersymmetry: brane dynamics, bubbles and holography

We present some results on instabilities of anti-de Sitter flux compactifications in effective field theories arising from non-supersymmetric string models, namely the USp(32) and U(32) orientifold models and the SO(16) x SO(16) heterotic model. We discuss perturbative and non-perturbative instabilities and frame the vacua in terms of brane stacks, analyzing their back-reacted geometry and reproducing AdS in the near-horizon limit. Then we describe the instabilities as branes separating from the stack, computing the associated decay rate matching a probe brane computation with the semi-classical Coleman-de Luccia result. We conclude briefly discussing possible implications regarding the fate of unstable vacua in string theory beyond the semi-classical limit, connecting this scenario to the Weak Gravity Conjecture, holographic renormalization group flows and to a "de Sitter on a brane" construction that was outlined in the recent literature.