FLAG FieLds And Gravity
Quantum Fields of Gravity, Cosmology and Black Holes

Scientific activities of the various Research Units


The UV-completion of QFT of gravity is investigated in the asymptotic safety paradigm, with particular interest in f(R) theories and the functional Hamiltonian measure for the RG flow of the effective action. A description of quantum horizons associated with (bound states of) elementary particles is being developed in order to investigate BEC of gravitons in inflation and as models of black holes, their role in the gravitational collapse of quantum matter and final stage of Hawking evaporation. QFT and string models of the early Universe, dark energy and dark matter are investigated, in order to understand how quantum-gravitational effects can influence the CMB radiation and other cosmological and astrophysical observables.


One of the specialities is QFT and strings in de Sitter and anti-de Sitter spaces, in particular the study of the perturbative infrared divergences, the role and physical meaning of the recently discovered family of de Sitter tachyons, the construction of explicit dS/AdS classical strings and their application in the Ads/CFT correspondence. Hawking radiation is investigated in analogue models of gravity, with particular attention to the theoretical modelling of the various effects in relation with concrete experimental setups and realisations. Various classical cosmological models, with Chaplygin gas, in f(R) theories, and gravity's rainbow modified geometry are analysed.


Aspects of inflation are investigated in relation to broken scale invariance and the vacuum energy, conformal field theories in FLRW spaces, and modified gravity theories (yielding one-loop quantum corrections to the slow-roll parameters). Also, classical solutions and quantum corrections are investigated in scale invariant theories of gravity. A perturbative analysis of the Higgs dark energy and its observational signatures is performed for the Euclid collaboration. Spherically symmetric solutions with matter are studied in Galileon-like theories, and analogue models of gravity are studied in condensed matter systems. Finally, there are research lines on black hole physics and the mathematical aspects of QFT using local algebraic methods.


On of the main lines is the search for a fixed point for gravity (coupled to matter) in f(R) theories, using functional renormalisation group techniques with various truncations. We also study the conformal properties of the putative fixed point, in order to understand the connection between asymptotic safety and classicalisation. Thermodynamical stability of regular black holes in AdS5 background is investigated, along with the holographic duality between Van der Walls fluids and AdS black holes, which could be of interest for the development of the AdS5/QCD duality, and the description of the quark-gluon plasma. Finally, unsolved issues in matter shell quantisation, mostly related with the quantum tunnelling, are studied.
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