“As our island of knowledge grows, so does the shore of our ignorance.” – John Archibald Wheeler, 1992 Gravity theory and GW phenomenology
Paolo Pani on behalf of the gravity-theory group web.uniroma1.it/gmunu Several of the deepest questions in fundamental physics involve gravity:
The nature of gravity. Is Einstein (still) right? What building-block principles and symmetries in nature invoked by General Relativity (GR) can be challenged? Are there extra fields involved in the gravitational interaction?
The nature of neutron stars. How does nuclear matter behave in the extreme conditions present in the inner core of neutron stars? Can we learn something on the non-perturbative regime of QCD? Does exotic physics show up in these objects?
The nature of black holes. Are the objects observed by LIGO-Virgo really the classical black holes of GR? Are there signatures of quantum gravity in the spacetime geometry of these compact objects? Do more exotic species of compact objects exist?
The nature of dark matter. Is dark matter composed of particles, dark objects, or modifications of the gravitational interaction? Can we detect or constrain dark matter by looking at its gravitational interaction with black holes and neutron stars?
2/11 Our group: web.uniroma1.it/gmunu
3/11 Our research
[keyword cloud by scimeter.org] 4/11 Research topics [web.uniroma1.it/gmunu/research]
GW modelling Neutron star physics
merger r Quasinormal modes of NSs
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o w the NS equation of state
n Tidal deformability & GWs
Gravity & astroparticles
Signatures of ultralight bosons Tests of gravity (e.g., axions) in curved spacetime
Compact objects in modified gravity Black-hole superradiance GW signals beyond GR Compact objects & dark matter BH ringdown tests of gravity Exotic compact objects
5/11 Some examples of research projects Modelling neutron-star (NS) binaries
Internal structure of a NS: NS coalescence:
ins pir post-merger al p oin t-p art icle
tid al effe cts
Post-Newtonian theory, tidal deformations, NS oscillations, ... GW170817: GW constraints on EoS can be combined with EM ones!
6/11 Black holes (BHs) beyond GR
GR is incomplete: it should be the first order in a high-curvature expansion
Extra fields
BHs can acquire new charges Dipolar radiation Novel ringdown modes
Numerical-relativity simulations (using supercomputers) of a BH coalescence in modified gravity
7/11 GW spectroscopy
BH ringdown is described by a set of quasinormal modes
No-hair theorem: quasinormal mode spectrum depends only on mass and spin 2 or more modes: tests of General Relativity!
8/11 GW spectroscopy
BH ringdown is described by a set of quasinormal modes
No-hair theorem: quasinormal mode spectrum depends only on mass and spin 2 or more modes: tests of General Relativity!
How to parametrize the ringdown? Ringdown tests with many sources
Overtones, are they important?
New physics at the horizon scale? GW echoes from exotic objects BH spectroscopy
8/11 New horizons
Lot of exciting work in the years to come!
Third-generation (3G) GW detectors: Einstein Telescope New theoretical and experimental challenges Members of the 3G Science Team Space mission LISA (ESA/NASA) Novel sources at low frequency (supermassive BHs, EMRIs, ...) Member of the LISA Consortium
9/11 Our network
Members of the Amaldi Research Center @ Sapienza
Members of COST Action “GWverse”, Network RISE “StrongGR”,
Coordination of TEONGRAV INFN initiative
ERC “DarkGRA” project [www.darkgra.org]
Members of the LISA Consortium
WPs: GW modelling, science interpretation, tests of GR
Members of the 3G Science Team
Members of the eXTP Science Team
Main collaborations: Lisbon (IST), Johns Hopkins U., SISSA, Tubingen U., King’s College, Perimeter Institute, Nottingham, Cambridge, Palma, Barcelona...
10/11 Studying gravity @ Sapienza
● “Relatività Generale” (Prof. Ferrari) → 6 crediti, LM
● “Onde gravitazionali, buchi neri, stelle di neutroni” (Prof. Gualtieri) → 6 crediti, LM
● “Experimental gravitation” (Prof. Ricci) → 6 crediti, LM
● Particle & Astroparticle physics, Introduzione alla gravità quantistica,
● Astrophysics, Cosmology, Compact objects... “Recording a GW […] has never been a big motivation for LIGO, the motivation has always been to open a new window to the Universe” – Kip Thorne (BBC interview, 2016) Backup slides
“Nothing is More Necessary than the Unnecessary” [cit.] Merger of two black holes [LIGO-Virgo Collaboration, PRL 116, 061102 (2016), PRL 116, 221101 (2016), PRL 116, 241102 (2016), ...]
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Nuove sfide e domande multidisciplinari:
Astro: rates binarie buchi neri, formazione buchi neri supermassivi, struttura stelle di neutroni, sorgenti raggi gamma,…
Fisica Fondamentale: equazione di stato ultranucleare, verifiche gravità, natura buchi neri, materia oscura, ... Merger of two black holes [LIGO-Virgo Collaboration, PRL 116, 061102 (2016), PRL 116, 221101 (2016), PRL 116, 241102 (2016), ...]
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merger n
g
d
inspiral o
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Nuove sfide e domande multidisciplinari:
Astro: rates binarie buchi neri, formazione buchi neri supermassivi, struttura stelle di neutroni, sorgenti raggi gamma…
Fisica Fondamentale: equazione di stato ultranucleare, verifiche gravità, natura buchi neri, materia oscura, ...