arXiv subjects

Alessandro Testa

Publications and source records attributed to Alessandro Testa.

7 recordsLinked to original sources

arXiv2026

Bootstrapping ABJM theory

Supersymmetric localization reduces the computation of protected observables in ABJM theory to finite-dimensional matrix integrals. Building on the techniques introduced in arXiv:2512.02119, we develop a bootstrap framework for the systematic calculation of instanton corrections to the free energy and to supersymmetric Wilson loops. Exploiting exact functional relations and consistency conditions satisfied by grand-canonical observables, in the Fermi-gas formulation of the ABJM matrix model, we provide analytic derivations of several relations for the free energy that were previously known only conjecturally, either from refined topological string theory or from high-precision numerical studies. We apply the same framework to determine the nonperturbative corrections to $1/2$ and $1/6$ BPS Wilson loops, elucidating their qualitative differences and uncovering novel structural features of the instanton effects. These results further highlight the intricate nonperturbative structure and network of dualities underlying ABJM theory.

hep-th↗

arXiv2025

Wilson loops in ABJM theory reloaded

We present a new technique for computing supersymmetric Wilson loops in the ABJM theory via supersymmetric localization, valid for arbitrary values of the rank of the gauge group $N$ and the Chern-Simons level $k$. The approach relies on an operator representation of the Wilson loops within the Fermi gas formalism in terms of the resolvent of a certain integral operator previously encountered in the computation of the ABJM partition function on the round three-sphere. By deriving a set of nontrivial relations for this resolvent, we obtain exact expressions for the generating functions of Wilson loops in terms of the partition function. For large $k$, these expressions reproduce the weak-coupling expansion of the Wilson loops, and in the large-$N$ limit at fixed $k$ they match previously obtained high-precision numerical results. This analysis also resolves the longstanding discrepancy between numerical data and the semiclassical expression for the $1/6$ BPS Wilson loop.

hep-th↗

arXiv2025

Correlation functions in four-dimensional superconformal long circular quivers

We study two- and three-point correlation functions of chiral primary half-BPS operators in four-dimensional $\mathcal{N}=2$ superconformal circular, cyclic symmetric quiver theories. Using supersymmetric localization, these functions can be expressed as matrix integrals which, in the planar limit, reduce to Fredholm determinants of certain semi-infinite matrices. This powerful representation allows us to investigate the correlation functions across the parameter space of the quiver theory, including both weak and strong coupling regimes and various limits of the number of nodes and the operator scaling dimensions. At strong coupling, the standard semiclassical AdS/CFT expansion diverges in the long quiver limit. However, by incorporating both perturbative corrections (in negative powers of the 't Hooft coupling) and an infinite tower of nonperturbative, exponentially suppressed contributions, we derive a remarkably simple expression for the correlation functions in this limit. These functions exhibit exponential decay with increasing node separation and admit an interpretation within a five-dimensional effective theory. We determine the mass spectrum of excitations propagating along the emergent fifth dimension within this theory, finding it to be given by the zeros of Bessel functions.

hep-th↗

arXiv2024

Deep Learning for Sea Surface Temperature Reconstruction under Cloud Occlusion

Sea Surface Temperature (SST) reconstructions from satellite images affected by cloud gaps have been extensively documented in the past three decades. Here we describe several Machine Learning models to fill the cloud-occluded areas starting from MODIS Aqua nighttime L3 images. To tackle this challenge, we employed a type of Convolutional Neural Network model (U-net) to reconstruct cloud-covered portions of satellite imagery while preserving the integrity of observed values in cloud-free areas. We demonstrate the outstanding precision of U-net with respect to available products done using OI interpolation algorithms. Our best-performing architecture show 50% lower root mean square errors over established gap-filling methods.

cs.CV↗

arXiv2024

Into the wedge of $\mathcal{N}=2$ superconformal gauge theories

We study $\frac{1}{4}$-BPS Wilson loops in four-dimensional SU$(N$) ${\mathcal{N}}=2$ super-Yang-Mills theories with conformal matter in an arbitrary representation $\mathcal{R}$. These operators are formed of two meridians on the two-sphere separated by an arbitrary opening angle. We conjecture that these observables are encoded in a modification of Pestun's matrix model. The matrix representation of these operators resembles that of the $\frac12$-BPS circular Wilson loop, differing only for a rescaling in the exponent. We compare the matrix model predictions with an explicit three-loop calculation in flat space based on standard Feynman-diagram techniques, finding perfect agreement. Finally, exploiting the matrix model representation of these Wilson loops, we study the large-$N$ limit at strong coupling of $\mathcal{N}=2$ superconformal QCD, finding a surprising transition in the vacuum expectation value for a critical opening angle.

hep-th↗

arXiv2024

1/2 BPS Wilson loops in non-conformal N = 2 gauge theories and localization: a three-loop analysis

We study the 1/2 BPS circular Wilson loop in four-dimensional SU(N), $N = 2$ SYM theories with massless hypermultiplets and non-vanishing $\beta$-function. Using super-symmetric localization on $S_4$ , we map the path-integral associated with this observable onto an interacting matrix model. Despite the breaking of conformal symmetry at the quantum level, we show that, within a specific regime, the matrix model predictions remain consistent with the perturbative results in flat space up to order $g^6$ . At this order, our analysis reveals that the reorganization of Feynman diagrams based on the matrix model interaction potential, widely tested in (super)conformal models, also applies to these non-conformal set-ups and is realized by interference mechanisms.

hep-th↗

arXiv2024

Supersymmetric localization and non-conformal $\mathcal{N}=2$ SYM theories in the perturbative regime

We examine the relation between supersymmetric localization on $\mathbb{S}^4$ and standard QFT results for non-conformal theories in flat space. Specifically, we consider 1/2 BPS circular Wilson loops in four-dimensional SU($N$) $\mathcal{N}$= 2 SYM theories with massless hypermultiplets in an arbitrary representation $\mathcal{R}$ such that the $\beta$-function is non-vanishing. On $\mathbb{S}^4$, localization maps this observable into an interacting matrix model. Although conformal symmetry is broken at the quantum level, we show that within a specific regime of validity the matrix model predictions are consistent with perturbation theory in flat space up to order $g^6$. In particular, at this order, localization predicts two classes of corrections proportional to $\zeta(3)$ whose diagrammatic origins in field theory are remarkably different. One class of $\zeta(3)$-like corrections emerges via interference effects between evanescent terms and the ultraviolet (UV) poles associated with the bare coupling constant, while the second one stems from a Feynman integral which retains the same form in flat space and on the sphere.

hep-th↗