Talks

The discovery of the Higgs boson at the Large Hadron Collider marks the culmination of a decades-long hunt for the last ingredient of the Standard Model. At the same time, this discovery has started a new era in the search for more fundamental physics. In this talk, I will discuss what we have learned from the Higgs discovery about the mechanism of electroweak symmetry breaking and the implications for the existence of additional Higgs bosons. I will then highlight the future prospects of the Higgs boson in shedding light on New Physics and in particular on the nature of Dark Matter.

We will discuss techniques for computing 4-point functions of local operators in 2D conformal field theories, and their implications for semiclassical 3D quantum gravity. For generic 4-point functions, we present new closed-form expansions of the Virasoro conformal blocks. Specializing to correlators of holomorphic operators, these can be efficiently and exactly determined using an analytic implementation of the conformal bootstrap. Applying this method to the sewing construction of 2D CFT partition functions, we compute, via AdS/CFT, the semiclassical expansion of pure 3D quantum gravity around saddle point geometries of genus two; unlike at genus one, this expansion does not truncate at finite loop order.  

More than a decade after its discovery, cosmic acceleration still 
poses a puzzle for modern cosmology and a plethora of models of dark energy 
or modified gravity, able to reproduce the observed expansion history, have 
been proposed as alternatives to the cosmological standard model. In recent 
years it has become increasingly evident that probes of the expansion his- 
tory are not sufficient to distinguish among the candidate models, and that 
it is necessary to combine those with observations that probe the dynamics 
of inhomogeneities. Future cosmological surveys will map the evolution of 
inhomogeneities to high accuracy, allowing us to test the relationships be- 
tween matter overdensities, local curvature, and the Newtonian potential on 
cosmological scales.

I will discuss theoretical issues involved in finding an optimal framework to 
study deviations from General Relativity on cosmological scales, giving an 
overview of recent progress, with a focus on model-independent, parametrized 
approaches. I will summarize where we stand and what are the next steps 
we should take.