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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
De Lorenzo Tommaso 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

86 results
Preprint, Working paper
Laurent Freidel, Alejandro Perez
Quantum gravity at the corner
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
Thibaut Josset, Goffredo Chirco, Carlo Rovelli
Statistical mechanics of reparametrization invariant systems. Takes Three to Tango
Classical and Quantum Gravity, IOP Publishing, 2016, 33, pp.045005
Journal article
Thomas Krajewski, Reiko Toriumi
Exact Renormalisation Group Equations and Loop Equations for Tensor Models
SIGMA (Symmetry, Integrability and Geometry: Methods and Applications), 2016, 〈10.3842/SIGMA.2016.068〉
Journal article
Thomas Krajewski, Reiko Toriumi
Polchinski's exact renormalisation group for tensorial theories: Gaussian universality and power counting
Journal of Physics A: Mathematical and General , IOP Publishing, 2016, 〈10.1088/1751-8113/49/38/38540〉
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
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)
Journal article
Miklos Långvik, Simone Speziale
Twisted geometries, twistors and conformal transformations
Physical Review D, American Physical Society, 2016, 94 (2)
Journal article
Carlo Rovelli, Francesca Vidotto
Compact phase space, cosmological constant, discrete time
Physical Review D, American Physical Society, 2016, 91 (8)
Journal article
Carlo Rovelli
An argument against the realistic interpretation of the wave function
Foundations of Physics, Springer Verlag, 2016, 46 (10), pp.1229 - 1237
86 results

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