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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

AMADEI Lautaro PhD candidate
Email
Gozzini Francesco 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
Chef de l’équipe « Gravité quantique »
+33.4.91.26.97.98 Email
Rovelli Carlo University faculty
+33.4.91.26.96.44 Email
Sarno Giorgio PhD candidate
Email
Speziale Simone Researcher
+33.4.91.26.95.46 Email

List of Publications

92 results
Journal article
Simone Speziale
Boosting Wigner's nj-symbols
Journal of Mathematical Physics, American Institute of Physics (AIP), 2017, 58 (3), pp.032501 ⟨10.1063/1.4977752⟩
Journal article
Marios Christodoulou, Tommaso de Lorenzo
Volume inside old black holes
Physical Review D, American Physical Society, 2016, 94 (10), ⟨10.1103/PhysRevD.94.104002⟩
Journal article
Jibril Ben Achour, Karim Noui, Alejandro Perez
Analytic continuation of the rotating black hole state counting
Journal of High Energy Physics, Springer Verlag (Germany), 2016, 2016 (08), pp.149. ⟨10.1007/JHEP08(2016)149⟩
Journal article
Tommaso de Lorenzo, Alejandro Perez
Improved Black Hole Fireworks: Asymmetric Black-Hole-to-White-Hole Tunneling Scenario
Physical Review D, American Physical Society, 2016, 93 (12), pp.124018. ⟨10.1103/PhysRevD.93.124018⟩
Preprint, Working paper
Eugenio Bianchi, Wolfgang Wieland
Horizon energy as the boost boundary term in general relativity and loop gravity
2016
Preprint, Working paper
You Ding, Muxin Han
On the Asymptotics of Quantum Group Spinfoam Model
2016
Book Section
Carlo Rovelli
Is Time's Arrow Perspectival?
Khalil Chamcham, Joseph Silk, John Barrow, Simon Saunders. The Philosophy of Cosmology , Cambridge University Press, 2016
Journal article
Hal M. Haggard, Carlo Rovelli
Quantum Gravity Effects around Sagittarius A*
International Journal of Modern Physics D, World Scientific Publishing, 2016, 25 (12)
Journal article
Carlo Rovelli
Gregory: Anaximander. A re-assessment
Revue des études anciennes, Revue des études anciennes, Université Bordeaux Montaigne, 2016, 118, pp. 657- 661
Journal article
Marios Christodoulou, Carlo Rovelli, Simone Speziale, Ilya Vilensky
Realistic Observable in Background-Free Quantum Gravity: the Planck-Star Tunnelling-Time
Physical Review D, American Physical Society, 2016, 94 (8)
92 results

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