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GAST GAUGE AND STRING THEORIES
Non-perturbative Dynamics in Gauge and String Theories

 
 
Coordinator: Davide Fioravanti
 
E-mail: davide.fioravanti at bo.infn.it, Phone: +39 051 20 91078 

Group members

Click on (pub) for a list of publications from Inspire

Staff
Postdocs
 
PhD students 

Research Activities

Quantum field theory is the primary tool in theoretical physics to describe the behaviour of elementary particles and fundamental interactions. Its applicability extends also to critical phenomena in statistical mechanics and condensed matter. At the moment we have an excellent control of quantum field theory at perturbative level while a full understanding of non-perturbative effects is the subject of research nowadays. This can be achieved via approaches based on the renormalisation group, holography and dualities, supersymmetry and integrability which allow the emergence of algebraic and analytic structures that can lead to the discovery of exact results.

Our activities focus on various aspects of quantum field theory and string theory, including: 

  • Worldline methods: First quantisation techniques whose goal is to find new representations of scattering amplitudes and effective actions in QFT with gauge and gravitational couplings, with string inspired methods [F. Bastianelli].
  • Integrability is a fundamental property of a class of theories that allows to calculate exactly non-trivial physical properties of a given system, thanks to an underlying mathematical and physical structure. In general, this property becomes manifest in a natural way in 2D systems, but can be present in more hidden forms in D>2.
    • Thermodynamic Bethe Ansatz: in integrable quantum field theories it is possible to consider, in an exact and unified way, the problems of thermodynamic behaviour and finite volume effects, using the Thermodynamic Bethe Ansatz (TBA). The development of the mathematical structures underlying TBA has revealed surprising algebraic and analytical textures, connected to other lines of research in mathematics and physics, which are under active investigation nowadays [D. Fioravanti, F. Ravanini].
    • Integrability in supersymmetric theories in 4D and strings: In higher dimensions, integrability becomes more subtle and even more remarkable. Our interest is towards supersymmetric gauge theories in 4D, which also feature phenomenological applications, and their relationship with string theories, where the bidimensional structure automatically leads to integrability. Our final goal is to formulate models that are more fundamental and therefore can provide realistic description of the interactions [D. Fioravanti, D.Gregori, H.Poghosyan].
    • Integrability in non-equilibrium physics is one of the major challenges of modern statistical mechanics. Recent developments have highlighted the existence of QFT methods to study these phenomena, not just at classical, but also at quantum level where they are related to the physics of cold atoms and bosonic condensates. The “quantum quench” approach is now mature, while generalised hydro-dynamics (GHD) is in an active phase of recent development. Integrability and non-perturbative physics play a crucial role in both approaches. [O. Pomponio,F. Ravanini].
  • Topological and geometrical aspects of quantum field theory and strings: Non-linear sigma models. Batalin-Vilkovisky quantisation using the geometrical formulation of Alexandrov-Kontsevich-Schwartz-Zaboronsky. Higher gauge theories [R. Zucchini].
  • Anomalies describe the quantum breaking of classical symmetries. They have several applications which range from constraining the matter content of gauge theories to the  characterisation of non-perturbative properties of QFT and their behaviour under the action of the renormalisation group [F. Bastianelli].

Collaborations

  • Prof. Christian Schubert (Universidad Michoacana, Morelia, Messico) 
  • Dr. James Edwards (Universidad Michoacana, Morelia, Messico) 
  • Dr. Naser Ahmadiniaz (Institute for Basic Science, Gwangju, South Korea) 
  • Dr. Roberto Tateo (University of Torino, Italy)
  • Prof. Andrew Waldron (University of California at Davis, USA)
  • Dr. Pablo A.G. Pisani (Universidad Nacional de La Plata, La Plata, Argentina) 
  • Prof. Thanu Padmanabhan (IUCAA, Pune University, Pune, India) 
  • Dr. Benjamin Doyon (King’s College, London, UK)
  • Dr. Olalla Castro-Alvaredo (City University, London, UK)
  • Prof. Changrim Ahn (Ewha Womans University, Seoul, South Korea)
  • Prof. Paul A. Pearce (University of Melbourne, Australia)