A corpuscular model of the gravitational interaction

by Dr Andrea Giugno

Hans Bethe Meeting Room (TIFPA)

Hans Bethe Meeting Room


Via Sommarive, 14 - Trento
We discuss the most recent developments in the field of corpuscular gravity,  with particular emphasis on models of toy gravitons coupled to static matter currents in a spherically symmetric setting. system of bosons can be self-confined in a volume of the size of the Schwarzschild radius, whose geometry is expected to arise as effective description of a ``Newtonian-like” framework. The classical field reproduces the Newtonian potential generated by the source, while the corresponding quantum state is given by a coherent superposition of scalar modes with continuous occupation number. Moreover, the study of the Hamiltonian constraint leads to an effective quantum description of the static gravitational potential up to the first post-Newtonian order. We show that one can functionally reproduce the classical Newtonian results very accurately by employing a coherent quantum state in such a way to include the first post-Newtonian corrections. Finally, we establish the natural extension of this scheme to cosmology, since it can lead to an inflationary model similar to Starobinsky'sone, all without requiring the introduction of the inflatonfield. All relevant properties are determined by the number of gravitons in a cosmological condensate and the correct particle spectrum is recovered, when the theory is linearisedon a curved background. The slow-roll out of the inflationary phase is realisedin terms of pure (corpuscular) gravity, by understanding the Einstein-Hilbert term of the action as a perturbation.