New frontiers of integrable deformations
Villa Garbald, Castasegna (CH)
 
Scope
Quantum field theory (QFT) is one of the most successful frameworks for studying a
wealth of physical phenomena, ranging from the interactions of fundamental particles
to condensedmatter systems. It is an ongoing challenge to understand quantum field
theories exactly, i.e. without resorting to perturbation theory. A historically successful
strategy is to restrict to theories simple enough to be exactly solvable, yet nontrivial
enough to capture interesting physics. In the case of interacting quantum field theories, exactly solvable models can most
often be found in two dimensions. These can be divided in two families:
twodimensional conformal field theories (CFTs), and twodimensional integrable
quantum field theories (IQFTs). Unsurprisingly in view of their very constrained
nature, these theories are like rare gems: as precious for advancing our understanding
as they are hard to find. It is therefore natural to ask, given an exactly solvable theory,
whether it is possible to deform it, perhaps spoiling some of its symmetries, but
preserving its exact solvability.
Recently integrable deformations stemming from composite operators constructed out of two conserved currents attracted much attention. Perhaps the most striking example of such deformations is given by the socalled TTbar deformations, which are constructed out of the product of two components of the stressenergy tensor. These deformations, first introduced by A.B. Zamolodchikov in 2004, were studied in detail by Zamolodchikov & Smirnov and by R. Tateo and collaborators in 2016. It was understood that the flow that they generate preserves exact solvability of a theory, and acts in a simple way on the spectrum. Moreover, these deformations appear naturally in string theory and seem to allow for a gravitational interpretation. In parallel, there has been remarkable activity in the study of integrable deformations of stringtheory backgrounds and supersymmetric nonlinear sigma model, in particular in the framework of “YangBaxter deformations”. While conceptually separate, many interesting similarities between these two frameworks are emerging. Many aspects remain to be explored, especially concerning the geometrical and gravitational (or stringtheoretical) interpretation of these deformation, their application to nonlinear sigma models, WessZuminoNovikovWitten models, as well as their role in the AdS/CFT correspondence and. The goal of this workshop is to bring together experts in all these topics for an open exchange of ideas, which we expect will lead to new collaborations and interesting results across all these fields. Invited participants
Location and travel
Villa Garbald is a facility of ETH Zurich, but is not located in Zurich. Rather it is right on the border with Italy, between Chiavenna and Bregaglia. It takes little less than 5 hours to get there from Zurich, and little less than 4 from Milan (by public transport; coming by car takes 3h and 2h30, respectively).
For longdistance buses to Zurich and Chur see e.g. www.flixbus.ch. For local trains in Lombardia (the Milano region) see www.trenord.it. Organiser
Alessandro Sfondrini (ETH Zurich).


The conference is supported by the Swiss National Science Foundation through the Scientific Exchanges scheme and by the Garbald fund.
Background image credits Demetrio Gregorini. 