General Relativity (GR) is a good description of gravity on a huge range of scales, field strengths and velocities. However, despite its successes, GR has been showing its age. Cosmological data supports the existence of a Dark Sector, which may be signalling the breakdown of our understanding of gravity. Also, at high energies, GR needs to be completed with 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 coincidental 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 behavior of the Universe (without introducing any Dark Energy and/or Dark Matter). These theories are characterized by non-perturbative screening mechanisms which allow to recover GR on local scales, where it is very well tested, while, at the same time, having sizable cosmological effects. However, it is still unclear whether these mechanisms work also in highly dynamical systems as the merger of binary compact objects.
The gravitational emission in such theories is much more involved than in GR, and has never been performed so far. Its computation will be a huge step forward for our understanding of cosmology, and it would definitely confirm or rule out modified gravity as a candidate for the Dark Sector. GRAMS will provide the first numerical-relativity simulations of compact binaries ever in gravitational theories of interest for cosmology.
Proposal duration 60 months
GRAVITY FROM ASTROPHYSICAL TO MICROSCOPIC SCALES
This project has received funding (to E. Barausse) from the European Research Council (ERC) under the European Union Horizon 2020 research and innovation programme (grant agreement no. GRAMS-815673; project title “GRavity from Astrophysical to Microscopic Scales”).
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Enrico Barausse - Associate Professor
Scuola Internazionale Superiore di Studi Avanzati
Office A-531 (Main building- East)
Via Bonomea, 265, 34136 Trieste TS, Italy
+39 040 3787 867 (office)