FLAG

Quantum Fields in Gravity, Cosmology and Black Holes

Scientific activities of the various Research Units

BOLOGNA

• We  investigate  the Ultraviolet completion of quantum  gravity, interacting with other fields using the Functional Renormalization Group technique in the framework of the Asymptotic Safety approach. We develop different version of the Renormalization group formalism and its applications to the quantum field theory in  curved spacetimes. 
• The new approaches to the classical and quantum physics of black holes are under study. Between these  approaches are Bootstrapped Newtonian Gravity and Horizon Quantum Mechanics. We will hence continue to develop the HQM and BNG in order to study quantum processes in the gravitational collapse of compact (astrophysical) objects that could possibly be seen by means of gravitational wave detectors and other observations.
•  We shall continue to study the physics both of the very early and late-time universe. The very early stages may be greatly influenced by Quantum Gravity effects and are then closely connected with the development of quantum cosmology.  We shall apply the cosmological Wheeler-DeWitt equation to the structure of the CMBR and generalise our formalism and results to MGT. General aspects of the QFT of constrained systems will be analysed as well.
• The problem of singularity in gravitational theories is studied in both cosmological and black holes contexts. 

CATANIA

We plan to investigate on the expected connection, though not clearly understood, between the continuum limit realized in the Asymptotic Safety (AS) scenario and Horava-Lifshitz gravity. In fact, in the first case there are strong indications that the UV region of the theory  is characterized by a non-gaussian fixed point for which the (negative) anomalous dimension of the (background) graviton is dynamically generated through a non-pertubative mechanism, while in the case of the HL gravity, the anomalous scaling is explicitly realized in the bare lagrangian. In particular, starting from the studies (Zappala' 2018)  that we recently carried out on the peculiar properties of the Lifshitz  points, we intend to analyze in detail the UV and IR structure of of higher derivative  theories that possess this kind of fixed points, either isotropic or anisotropic, in order  to achieve a clearer picture of their phase diagram. In addition we hope to achieve a better understanding of the nature of possible unphysical modes such as tachyons or negative norm states, etc, in relation with the structure of the vacuum as this latter can be non-trivial in these theories.

MILANO

• Quantum fields on the de sitter universes
• General analysis of the effects of dispersion and absorption in analogue gravity systems.
• Geometric methods for computing general Feynman amplitudes in quantum and classical perturbative theories, in particular with techniques of algebraic geometry and (co)homology.
• Determination of the main thermodynamic properties of pasta states in the Skyrme approximation.
• Non supersymmetric multi-black hole solutions in gauged supergravity, with one supersymmetric horizon.
• General analysis of the obstruction to splitting in supergeometry and its applications to super string theory.
• Dark cosmology

TRENTO

The research interests of the Trento node span from modified gravity and related phenomenology, to quantum field theory in curved space, quantum gravity, and analogue models of gravity.

• In the field of modified gravity ( e.g. f(R), Horndeski and beyond) we study exact black hole solutions together with inflationary models and strange stars in quadratic gravity.
• Concerning field theory, we are focussed on the cosmological implications of the false-vacuum decay à la Coleman-De Luccia in modified gravity, especially in relation to the Higgs decay. We are also considering black hole models derived from Loop Quantum Gravity when the Immirzi parameter becomes a dynamical field.
• The questions that we are investigating in the context of quantum gravity are the applications of quantum information theory to information loss in black holes, the theory of space-time singularities and regular black holes, and the holographic approach to the cosmological constant problem.
• Finally, we are also involved in theoretical and experimental simulations of black holes and the inflationary universe in Bose-Einstein condensates.

TRIESTE

• metric-affine gravity 
• higher derivative gravity
• asymptotic safety both in gravity and particle physics models going beyond the standard model
• non-singular cosmologies 
• baby universes
• black holes.