Centre de Physique Théorique

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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
Gozzini Francesco PhD candidate
Krajewski Thomas University faculty
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Martin-Dussaud Pierre PhD candidate
Martinez Daniel PhD candidate
Perez Alejandro University faculty
Chef de l’équipe « Gravité quantique »
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Rovelli Carlo University faculty
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Sarno Giorgio PhD candidate
Speziale Simone Researcher
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List of Publications

92 results
Carlo Rovelli
Sette brevi lezioni di fisica
Adelphi, 666, 2014, Piccola Biblioteca Adelphi, 9788845929250
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
Julian Rennert, David Sloan
A Homogeneous Model of Spinfoam Cosmology
Classical and Quantum Gravity, IOP Publishing, 2013, 30 (23), pp.235019. ⟨10.1088/0264-9381/30/23/235019⟩
Journal article
Nicolas B. Cowan, Pablo A. Fuentes, Hal M. Haggard
Lightcurves of Stars & Exoplanets: Estimating Inclination, Obliquity, and Albedo
Monthly Notices of the Royal Astronomical Society, Oxford University Press (OUP): Policy P - Oxford Open Option A, 2013, 434 (3), pp.2465-2479. ⟨10.1093/mnras/stt1191⟩
Conference paper
Simone Speziale
Loop quantum gravity, twistors, and some perspectives on the problem of time
2nd International Conference on New Frontiers in Physics (ICNFP 2013), Aug 2013, Kolymbari, Crete, Greece. pp.00123, ⟨10.1051/epjconf/20147100123⟩
Journal article
Andreas G. A. Pithis
The Gibbs paradox, Black hole entropy and the thermodynamics of isolated horizons
Physical Review D, American Physical Society, 2013, 87, pp.084061. ⟨10.1103/PhysRevD.87.084061⟩
Journal article
Christian Röken
First-order quantum-gravitational correction to Friedmannian cosmology from covariant, holomorphic spinfoam cosmology
International Journal of Modern Physics D, World Scientific Publishing, 2013, 22 (02), pp.1350005. ⟨10.1142/S0218271813500053⟩
Journal article
Edward Wilson-Ewing
The Matter Bounce Scenario in Loop Quantum Cosmology
Journal of Cosmology and Astroparticle Physics, Institute of Physics (IOP), 2013, 2013 (3), pp.026. ⟨10.1088/1475-7516/2013/03/026⟩
Journal article
Hal M. Haggard, Carlo Rovelli
Death and resurrection of the zeroth principle of thermodynamics
Physical Review D, American Physical Society, 2013, 87 (8), pp.084001
92 results