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Quantum Gravity

Group “Fundamental Interactions”

The QG equipe works on a major unsolved question in fundamental physics: understanding the quantum properties of gravity. Since gravity is the dynamics of spacetime, this amount to study the quantum behaviour of time and space.

Loop Quantum Gravity (LQG), is a main approach towards the solution of this problem, and the CPT is a leader in this field. The group works on the formal definition of the theory, its mathematical aspects, and its applications.

Among the formal developments, the group is studying the properties of the coherent semiclassical states which describe quantum geometry, and is developing a reformulation of the theory in terms of twistors which should simplify its application.

The main applications are to early cosmology and to black hole physics. The objective of the research is to find observable phenomena that could test the theory empirically.

In the context of early cosmology, LQG allows to explore the region around the initial singularity predicted by classical general relativity. The theory indicates that the present expansion phase was preceded by a contraction phase.

In the context of Black hole physics, LQG opens the possibility to study the physics of the high-curvature region (the “Planck star”), suggesting that the singularity predicted by classical general relativity is cured by quantum effects. A black hole is consequently unstable: it can explode via a quantum tunnelling process, akin to conventional radioactive nuclear decay. The equipe studies the signals produced by such black hole explosions. One hypothesis is that currently observed astrophysical phenomena such as very-high-energy gamma rays or Fast Radio Bursts could be originated by such a quantum gravitational explosion of primordial black holes.

The quantum structure of spacetime is also relevant for the thermal properties of the black holes and for the so-called black-hole “information paradox”. The group is at the forefront of the analysis of these questions.

Directory of Members

D’Ambrosio Fabio PhD candidate
Email
Krajewski Thomas University faculty
+33.4.91.26.95.61 Email
Liu Hongguang PhD candidate
Email
Martin-Dussaud Pierre PhD candidate
Email
Martinez Daniel PhD candidate
Email
Perez Alejandro University faculty
+33.4.91.26.97.98 Email
Rovelli Carlo University faculty
Chef de l’équipe « Gravité quantique »
+33.4.91.26.96.44 Email
SARNO Giorgio PhD candidate
Email
Saul Andres Guest
Email
Speziale Simone Researcher
+33.4.91.26.95.46 Email
Vidotto Francesca Guest
Email

List of Publications

90 results
Conference paper
Reiko Toriumi, Herbert W. Hamber
On the cosmological constant: its identification as renormalization group invariant scale corresponding to a gravitational condensate
Frontiers of Fundamental Physics 14 - FFP14, Jul 2014, Marseille, France. FFP14 (178), Proceedings of Science
Journal article
Amit Ghosh, Karim Noui, Alejandro Perez
Statistics, holography, and black hole entropy in loop quantum gravity
Physical Review D, American Physical Society, 2014, 89 (8), pp.084069. 〈10.1103/PhysRevD.89.084069〉
Preprint, Working paper
Carlo Rovelli
Why do we remember the past and not the future? The 'time oriented coarse graining' hypothesis
2017
Preprint, Working paper
Carlo Rovelli
Lorentzian Connes Distance, Spectral Graph Distance and Loop Gravity
2017
Journal article
A. Barrau, Carlo Rovelli, Francesca Vidotto
Fast Radio Bursts and White Hole Signals
Physical Review D, American Physical Society, 2014, 90, pp.127503. 〈10.1103/PhysRevD.90.127503〉
Journal article
Tomasz Pawlowski, Roberto Pierini, Edward Wilson-Ewing
Loop quantum cosmology of a radiation-dominated flat FLRW universe
Physical Review D, American Physical Society, 2014, 90 (12), pp.123538 〈10.1103/PhysRevD.90.123538〉
Journal article
Carlo Rovelli, Francesca Vidotto
Planck stars
International Journal of Modern Physics D, World Scientific Publishing, 2014, 23 (12), pp.1442026. 〈10.1142/S0218271814420267 〉
Book
Carlo Rovelli, Francesca Vidotto
Covariant Loop Quantum Gravity
Cambridge University Press, 2014, 9781107069626
Book
Carlo Rovelli
Sette brevi lezioni di fisica
Adelphi, 666, 2014, Piccola Biblioteca Adelphi, 9788845929250
Journal article
Thomas Krajewski, Reiko Toriumi
Polchinski's equation for group field theory
Fortschritte der Physik / Progress of Physics, 2014, 62 pp.855-862. 〈10.1002/prop.201400043〉
90 results

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