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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

Krajewski Thomas University faculty
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ODAK Gloria PhD candidate
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Perez Alejandro University faculty
Chef de l’équipe « Gravité quantique »
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RIBISI Salvatore PhD candidate
RIGNON BRET Antoine PhD candidate
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Rovelli Carlo Emeritus
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Saul Andres Guest
Speziale Simone Researcher
Chef du Groupe « Interactions fondamentales »
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VIOLLET Sami PhD candidate
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List of Publications

130 results
Journal article
Fabio Anzà, Simone Speziale
A note on the secondary simplicity constraints in loop quantum gravity
Classical and Quantum Gravity, 2015, 32 (19), pp.195015. ⟨10.1088/0264-9381/32/19/195015⟩
Journal article
Hal M. Haggard, Carlo Rovelli
Black hole fireworks: quantum-gravity effects outside the horizon spark black to white hole tunneling
Physical Review D, 2015, 92 (10), pp.104020. ⟨10.1103/PhysRevD.92.104020⟩
Journal article
Olivier Asin, Jibril Ben Achour, Marc Geiller, Karim Noui, Alejandro Perez
Black holes as gases of punctures with a chemical potential: Bose-Einstein condensation and logarithmic corrections to the entropy
Physical Review D, 2015, 91 (8), pp.084005. ⟨10.1103/PhysRevD.91.084005⟩
Journal article
Sergey Alexandrov, Simone Speziale
First order gravity on the light front
Physical Review D, 2015, 91 (6), pp.064043. ⟨10.1103/PhysRevD.91.064043⟩
Journal article
A. Barrau, Carlo Rovelli
Planck star phenomenology
Physics Letters B, 2014, 739, pp.405-409 ⟨10.1016/j.physletb.2014.11.020⟩
Journal article
Alejandro Perez
Statistical and entanglement entropy for black holes in quantum geometry
Physical Review D, 2014, 90 (8), pp.084015. ⟨10.1103/PhysRevD.90.084015⟩
Book Section
Abhay Ashtekar, Martin Reuter, Carlo Rovelli
From General Relativity to Quantum Gravity
International Society for General Relativity and Gravitation. General Relativity and Gravitation: A Centennial Survey, Cambridge University Press, 2014
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
Conference paper
Alejandro Perez
Black hole entropy and entanglement of Planckian degrees of freedom
Frontiers of Fundamental Physics 14, Jul 2014, Aix Marseille University (AMU) Saint-Charles Campus, France. pp.173, ⟨10.22323/1.224.0173⟩
Conference paper
Enrico Calloni, S Caprara, Martina de Laurentis, Giampiero Esposito, M Grilli, Ettore Majorana, G P Pepe, S Petrarca, P Puppo, F Ricci, Luigi Rosa, Carlo Rovelli, P Ruggi, N L Saini, Cosimo Stornaiolo, Francesco Tafuri
The Archimedes project: a feasibility study for weighing the vacuum energy
Frontiers of Fundamental Physics 14 - FFP14, Jul 2014, Aix Marseille University (AMU) Saint-Charles Campus, Marseille, France
130 results