Strings, Gravity, and Quantum Fields
String Theory is the most viable candidate as a quantum theory describing all fundamental interactions, including gravity. In our research activity, we explore its implications for low-energy physics, supergravity models and applications to phenomenology, the properties of black holes, and non-perturbative dynamics of quantum fields. We use and develop techniques based on symmetries, integrability, algebraic and geometrical methods, holography and other non-perturbative dualities.
Staff
Full Professors: Gianguido Dall’Agata, Luca Martucci, Fabio Zwirner
Associate Professors: Kurt Lechner, Pieralberto Marchetti, Stefano Massai, Marco Matone, Alessandro Sfondrini, Roberto Volpato
Assistant Professors: Fabio Apruzzi
Post-doc
Maxim Emelin,Matheus Augusto Fabri, Stefano Gregorio Giaccari, Davide Polvara, Antons Pribytoks, Torben Skrzypek
PhD students
Francesco Bedogna, Fabio Billiato, Niccolò Risso, Davide Rovere, Enrico Turetta
External collaborators
Davide Cassani (staff INFN), Alessandra Gnecchi (staff INFN), Jessica Hutomo (assegnista INFN), Gianluca Inverso (staff INFN), Angel Murcia (assegnista INFN), Dmitri Sorokin (staff INFN), Colin Sterckx (assegnista INFN)
Research activities
Low-energy physics in string theory and quantum gravity
This research line investigates the characteristic features of the low-energy effective field theories compatible with string theory and quantum gravity. In this context, our group studies the structure of the low-energy effective actions, the possible supersymmetry breaking mechanisms, the geometric and non-geometric structures of string compactifications, the physical implications of branes and non-perturbative effects, and the general low-energy constraints imposed by quantum gravity.
Contacts: Apruzzi, Dall’Agata, Gnecchi, Martucci, Zwirner
Dualities and conformal invariance in field theory
Dualities such as Wegner, electric-magnetic and S-duality, are fundamental tools to study properties of lattice, field, string and brane theories in regimes where perturbative approximations do not hold. An activity of our group focuses on the analysis of duality-invariant gauge theories and their weak and strong field limits. Among this type of theories, a vivid attention has been attracted by a recently found "ModMax", a unique non-linear extension of Maxwell's electrodynamics which is conformal and duality invariant. The study of ModMax has opened different new perspectives of developments, in particular in the context of black hole physics and within a new class of energy-momentum tensor (so called TTbar and root-TTbar) deformations of field theories in various dimensions.
Contacts: Lechner, Marchetti, Sfondrini, Sorokin
Black holes and holography
The black hole information paradox is a vivid manifestation of the difficulties that arise in formulating a theory of gravity according to the principles of quantum mechanics. In our group we use a variety of tools in string theory and holography to advance in our understanding of the microscopic properties of black holes. In particular, advanced techniques in supersymmetric quantum field theory are used to match the macroscopic and microscopic entropy of black holes. We also aim at identifying the black hole microstates by using both supergravity and worldsheet techniques
Contacts: Cassani, Dall’Agata, Gnecchi, Massai
Integrable models and their applications to string theory
The study of integrable systems (systems which are exactly solvable owing to their symmetries) has marked the evolution of theoretical physics, from Kepler's problem to the Ising model. Our study focuses on integrable quantum systems which we study via a "bootstrap" based on conditions of analyticity, unitarity and symmetry, as well as from an algebraic point of view. This has several applications: to string theory (especially in the context of holographic dualities), to field theory, to scattering amplitudes, as well as to mathematics with the study of quantum groups and toroidal algebras
Contacts: Sfondrini, Sorokin
Structure of supergravity theories
Duality symmetries play an important role in string theory and supergravity. Advanced geometrical tools such as generalized geometry and exceptional field theory allow one to surface how the structure of supergravity compactifications is governed by such duality groups. They provide especially powerful tools for studying the physical properties of both geometric and non-geometric configurations. The group works on both the formal aspects of exceptional geometries and field theories, as well as on physical applications.
Contacts: Cassani, Dall’Agata, Inverso, Martucci
Algebraic and geometrical methods in string theory
In recent years, a number of new fruitful synergies have emerged between string theory and number theory, algebra, and geometry. Our group is interested in providing a useful description of the correct integration measure on the supermoduli space of supersymmetric Riemann surfaces of genus g in terms of modular forms. This is a fundamental building block in the computation of g-loop superstring amplitudes. At non-perturbative level, we investigate the appearance of modular and automorphic in a number of related instances: in the couplings in low energy string effective actions, as generating functions of black hole microstate degeneracies, as topological invariants in enumerative geometry, and as characters of representations of infinite dimensional algebras.
Contacts: Matone, Volpato
Conformal field theory and applications
Conformal field theories are a fundamental tool in a wide range of physical models, from the description of fixed points in the renormalization flow, to critical points in statistical mechanical models, to string theory, to the holographic description of gravity theories. The activity of our group focuses on general properties of (super-)conformal field theories in two and four dimensions, in particular in their relations with AdS/CFT duality. Our goal is to obtain exact results using both purely algebraic methods (such as vertex operator algebras) or integrability techniques
Contacts: Sfondrini, Volpato
Non-perturbative QFT and generalized symmetries
Understanding the symmetries in quantum field theory (QFT) is of paramount importance in unraveling the fundamental principles governing physical systems. The goal of our research group is to investigate novel “generalized” symmetries in QFT, by examining holographic and string theory constructions of QFTs. In particular, our group seeks for applications to strongly coupled gauge theories and phenomenology, and aims to explore the fate of generalized symmetries in the realm of quantum gravity.
Contacts: Apruzzi, Cassani, Martucci
Nonperturbative aspects in gauge theory and High-Tc superconductivity
High Tc superconductivity in cuprates has at the moment no fully satisfactory explanation and cannot be described within a perturbative framework. Our group is investigating a non-perturbative approach to this problem, based on Chern-Simons theories, which is in good agreement with experimental data, and that involves several non-perturbative aspects that admit an interesting topological interpretation: anomalous braid statistics, quantum vortices and fractional quantum numbers, Haldane exclusion statistics, and the topological version of Luttinger theorem.
Contacts: Marchetti
Foundations of quantum mechanics
The quantum Hamilton-Jacobi equation and the continuity equation have a relevant role in a broad range of research topics, from the foundations of quantum mechanics to aspects of quantum gravity, as in the case of the Wheeler-DeWitt equation. It turns out that these equations reduce to a single one by introducing two vector fields. Aim of the research is to investigate the implications of such a formulation. Another topic is the study of Classical-Quantum duality resulting from the Fourier transform of the generating functional in QFT. A possible relationship between quantum mechanics and general relativity is investigated with the use of a recently found linear representation of Friedmann equations.
Contacts: Matone
