Descrizione del progetto
Spiegare l’energia oscura attraverso la gravità modificata
Da circa 100 anni la relatività generale riesce a descrivere con successo la gravità in una molteplicità di regimi. Tuttavia, per spiegare le osservazioni cosmologiche, dobbiamo introdurre componenti oscure, come la materia oscura e l’energia oscura, che rimangono un mistero. Inoltre, le recenti osservazioni LIGO/Virgo, e in particolare il rilevamento coincidente di segnali elettromagnetici e gravitazionali provenienti da binarie di stelle di neutroni, hanno avuto un enorme impatto sulla nostra comprensione teorica della gravità, limitando fortemente diverse estensioni della relatività generale. Il progetto GRAMS, finanziato dall’UE, si interroga circa la reale esistenza dell’energia oscura chiedendosi se essa possa essere interpretata piuttosto come un’alterazione della nostra comprensione della gravità. I ricercatori analizzeranno se gli attuali dati di LIGO/Virgo sono coerenti con le teorie gravitazionali costruite per riprodurre il comportamento su larga scala dell’universo.
Obiettivo
General Relativity (GR) describes gravity on a huge range of scales, field strengths and velocities. However, despite its successes, GR has been showing its age. Cosmological data support the existence of a Dark Sector, but may also be interpreted as a breakdown of our understanding of gravity. Also, GR is intrinsically incompatible with quantum field theory, and should be replaced, at high energies, by a (still unknown) quantum theory of gravity.
This deadlock may prelude to a paradigm change in our understanding of gravity, possibly triggered by the direct observations of neutron stars and black holes by gravitational-wave interferometers. The recent LIGO/Virgo observations, and in particular the coincident detection of electromagnetic and gravitational signals from neutron-star binaries, have already made a huge impact on our theoretical understanding of gravity, by severely constraining several extensions of GR.
GRAMS is a high-risk/high-gain project seeking to push the implications of these observations even further, by exploring whether the existing LIGO/Virgo data, and in particular their absence of non-perturbative deviations from GR, are consistent with gravitational theories built to reproduce the large-scale behaviour of the Universe (i.e. the existence of Dark Energy and/or Dark Matter), while at the same time passing local tests of gravity thanks to non-perturbative screening mechanisms. I will prove that the very fact of screening local scales makes gravitational emission in these theories much more involved than in GR, and also intrinsically unlikely to yield results in agreement with existing (and future) gravitational-wave observations. This would be a huge step forward for our understanding of cosmology, as it would rule out a modified gravity origin for the Dark Sector. Even if this conjecture is incorrect, GRAMS will provide the first numerical-relativity simulations of compact binaries ever in gravitational theories of interest for cosmology.
Campo scientifico
- natural sciencesphysical sciencesrelativistic mechanics
- natural sciencesphysical sciencesastronomystellar astronomyneutron stars
- natural sciencesphysical sciencesastronomyastrophysicsblack holes
- natural sciencesphysical sciencesastronomyastrophysicsdark matter
- natural sciencesphysical sciencesastronomyphysical cosmology
Parole chiave
Programma(i)
Argomento(i)
Meccanismo di finanziamento
ERC-COG - Consolidator GrantIstituzione ospitante
34136 Trieste
Italia