Quantum Field Theory is currently the best, extremely successful framework to describe all fundamental
interactions, apart maybe from Gravity. Gravity becomes strong at the scale of the whole Universe or in
the violent events like collisions of binary black holes, which can be observed by detecting the emitted
Gravitation Waves. Even though these processes are classical, tools to calculate the shape and the
amplitude of the signal are rooted in Quantum Field Theory as well.
What happens when the gravitational field is so strong that quantum effects cannot be neglected is
largely unknown. Perhaps String Theory can give us a clue, or maybe the best bet is to quantize gravity
in the non-relativistic regime more compatible with our everyday experience.
High Energy and Cosmology Subgroups
Quite remarkably, strong gravitational fields are capable to describe non-gravitational physics by means
of the Holographic Duality. Holography has numerous applications ranging from hadrons and their
interactions to strongly-correlated electrons. It also underlies those few models of Quantum Field
Theory where analytical control over quantum fluctuations can be extended to a fully non-perturbative
regime without any small parameters.
The mathematical structure of Quantum Field Theory is extremely rich, and over time has given rise to
the whole areas of modern geometry, algebra, and representation theory, while new mathematical ideas
constantly enrich our knowledge about the basic constituents of matter.