Theoretical Particle Physics - Upcoming seminars

E11 is known to predict the correct physical fields of all maximal supergravities in D > 2, plus any possible gauge deformation thereof. In this talk I will explain whether or not this correspondence also holds in D=2, where the global symmetry group is E9.

A central problem in quantum condensed matter physics is the critical theory governing the zero temperature quantum phase transition between strongly renormalized Fermi-liquids as found in heavy fermion systems and possibly high Tc superconductors. We show that string theory is able to describe such fermionic quantum critical states. Using the Anti-de-Sitter/Conformal Field Theory (AdS/CFT) correspondence to relate fermionic quantum critical fields to a gravitational problem, we compute the spectral functions of fermions in the field theory. By increasing the fermion density away from the relativistic quantum critical point, a state emerges with all the features of the Fermi-liquid.

In recent years Higgsless models have been considered following different approaches. The underlying idea is the possibility of a new strong interaction at the scale of few TeV, as in Technicolor case. However due to the theoretical difficulty in dealing with strong interacting theories, effective models have been considered. I will show you that moose models offer a good basis for this approach (also for their interpretation in five dimensions) and also that several old models can be reviewed within this framework. I will discuss the main problems affecting all these approaches, namely unitarity and agreement with electroweak experimental data. I will show that these two problems create a tension that it is possible to solve only at the expense of some fine tuning. Possible phenomenological implications for the physics at the LHC will be discussed.

The dynamical consistency of the non-projectable version of Hořava gravity is investigated by focusing on the asymptotically flat case. It is argued that for generic solutions of the constraint equations the lapse must vanish asymptotically, or even everywhere in particular cases. Put differently, the Hamiltonian constraints are generically all second-class, revealing a dynamical inconsistency of the theory. A seeming paradox will be resolved and implications of the result will be discussed.