Project

Unified theories; Supersymmetric field theories; Superstring theories; Supersymmetry; high-energy theory; particle theory

Lead
Lay summary
Particle physics theory in the last decades has been dominated by two broad lines of research. Firstly, the exploration of the Standard Model of strong and electroweak interactions, which has been so successfully confronted with experiments at all available energies. This exploration should be almost completed when results from LHC will test symmetry breaking and mass generation (and prove or disprove the existence of the Higgs boson). The second line of research aims at developing conceptual and theoretical frameworks for a better understanding of the foundations of the Standard Model and a more unified description of all particle interactions, including gravitation. The main conceptual tools used in this program are supersymmetry, unified symmetries, superstring theories and small extra dimensions. The present research project studies some aspects of supersymmetric field theories and superstring compactifications. Supersymmetry is used in unified descriptions of particle interactions mostly because it is an extension of space-time (Poincaré) symmetries linking bosons and fermions and because it helps to understand how scalar fields (like the Higgs boson field) could remain light with respect to heavier scales of particle physics (like the Planck scale). It is also present in superstring theories. In addition, supersymmetric quantum field theories have many interesting properties which give access to their nonperturbative regime. It is then an important tool in the study of strongly-coupled field theories. String theories have been intensively developed with three main applications in view. Firstly, as a candidate unified quantum theory of all fundamental particle interactions, including gravitation. Secondly, as a tool to study nonperturbative aspects of gauge field theories (via gauge-gravity dualities). Thirdly, as a theoretical framework for studying quantum gravitation. Within this research project, we intend to study the following problems. Firstly, the development of superstring solutions with four-dimensional spacetime symmetry using the effective gauged supergravity approach will be continued by considering non-geometric backgrounds and, when available, their world-sheet description. Secondly, various compactifications with smooth dependence on the anti-de Sitter curvature witll be described. Secondly, our description of D-brane (Born-Infeld) actions with nonlinear N=2 supersymmetry will be completed, in the framework of local supersmmetry. Thirdly, the moduli space of several chiral N=1 supersymmetric gauge theories, which defines the quantum vacuum manifold of the theory, will be studied using algebraic and superspace methods.

Direct link to Lay Summary

Last update: 21.02.2013

Active participation

Number	Title	Start	Funding scheme

Study of the microscopic, worldsheet structure of string compactifications on non-geometric backgrounds : chiral bosons, Lorentz and conformal invariance, space-time field equations and doubled field theory. Reformulation of these worldsheet theories as conformal field theories. General description of non-geometric string backgrounds using gaugings of N=4 supergravity theories. Study of classes of string compactifications on curved internal manifolds. In the context of orientifold compactifications of type II strings, construction and study of supersymmetric brane Dirac-Born-Infeld Lagrangians with a second nonlinear supersymmetry : scalar potential and stability equations of the string configuration.Derivation of the chiral ring and anomaly study of N=1 supersymmetric gauge theories with maximally chiral matter supermultiplets.