Foto del docente

Roberto Casadio

Associate Professor

Department of Physics and Astronomy "Augusto Righi"

Academic discipline: FIS/02 Theoretical Physics, Mathematical Models and Methods

Research

Keywords: Black holes Cosmology Quantum theories of gravitation Quantum field theory

Quantum theories of gravity; quantum field theory on curved spaces; semiclassical and quantum aspects of gravitational collapse, cosmology and black holes.

The main object of study is the interaction of gravity with quantum matter in order to derive observable effects in cosmology, the astrophysics of gravitational collapse and black holes. The research program plans to cover both formal and phenomenological aspects: Among the former we mention the development of theories describing matter and gravitation, including both traditional quantum field theories on curved space-time and general relativity, and fully quantum approaches in which the classical spacetime emerges from the quantum state of the Universe. An aspect common to many recent formal developments is the prediction of non-commutativity of space-time coordinates on very short scales or, equivalently, the existence of a minimum reachable length at very high energy scales. An argument supporting this conclusion is the prediction that sufficiently compact objects become black holes. To deal with this specific aspect, an approach called horizon quantum mechanics has been developed which treats the gravitational radius as an observable and allows us to derive a generalized uncertainty principle. Furthermore, non-commutativity could remove the divergences suffered by quantum field theories, without the need to resort to regularization procedures, but granting their completeness at high energies. Other unsolved problems are the present acceleration of the Universe and the effects commonly associated with the existence of dark matter, for which a unified model based on the quantum properties of the universe as a whole is being developed. An essential aspect is given by the non-linearity of the gravitational interaction in the quantum theory, for which we have developed an approach called bootstrapped Newtonian gravity.