Results 31 to 40 of about 5,789 (259)
Diffeomorphism Symmetry in Quantum Gravity Models [PDF]
Advanced Science Letters, 2009 We review and discuss the role of diffeomorphism symmetry in quantum gravity models. Such models often involve a discretization of the space-time manifold as a regularization method. Generically this leads to a breaking of the symmetries to approximate ones, however there are incidences in which the symmetries are exactly preserved.
openaire +2 more sources
Comparing Quantum Gravity Models: String Theory, Loop Quantum Gravity, and Entanglement Gravity versus SU(∞)-QGR [PDF]
Symmetry, 2022 In a previous article we proposed a new model for quantum gravity (QGR) and cosmology, dubbed SU(∞)-QGR. One of the axioms of this model is that Hilbert spaces of the Universe and its subsystems represent the SU(∞) symmetry group. In this framework, the classical spacetime is interpreted as being the parameter space characterizing states of the SU ...
openaire +4 more sources
Journal of High Energy Physics, 2021 We study the genus expansion on compact Riemann surfaces of the gravitational path integral Z grav m $$ {\mathcal{Z}}_{\mathrm{grav}}^{(m)} $$ in two spacetime dimensions with cosmological constant Λ > 0 coupled to one of the non-unitary minimal models ...
Dionysios Anninos, Beatrix Mühlmann
doaj +1 more source
Discrete Gravity Models and Loop Quantum Gravity: a Short Review [PDF]
Symmetry, Integrability and Geometry: Methods and Applications, 2012 v2: many amendments, matches published ...
Dupuis, Maite +2 more
openaire +5 more sources
Two dimensional nearly de Sitter gravity
Journal of High Energy Physics, 2021 We study some aspects of the de Sitter version of Jackiw-Teitelboim gravity. Though we do not have propagating gravitons, we have a boundary mode when we compute observables with a fixed dilaton and metric at the boundary.
Juan Maldacena +2 more
doaj +1 more source
Dilaton gravity, Poisson sigma models and loop quantum gravity [PDF]
Classical and Quantum Gravity, 2009 31 ...
Bojowald, Martin, Reyes, Juan D.
openaire +2 more sources
NEW SPIN FOAM MODELS OF QUANTUM GRAVITY [PDF]
Modern Physics Letters A, 2005 We give a brief and a critical review of the Barret-Crane spin foam models of quantum gravity. Then we describe two new spin foam models which are obtained by direct quantization of General Relativity and do not have some of the drawbacks of the Barret-Crane models.
openaire +3 more sources
2D gravitational Mabuchi action on Riemann surfaces with boundaries
Journal of High Energy Physics, 2017 We study the gravitational action induced by coupling two-dimensional non-conformal, massive matter to gravity on a Riemann surface with boundaries. A small-mass expansion gives back the Liouville action in the massless limit, while the first-order mass ...
Adel Bilal, Corinne de Lacroix
doaj +1 more source
MINISUPERSPACE MODEL FOR REVISED CANONICAL QUANTUM GRAVITY [PDF]
International Journal of Modern Physics D, 2004 We present a reformulation of the canonical quantization of gravity, as referred to the minisuperspace; the new approach is based on fixing a Gaussian (or synchronous) reference frame and then quantizing the system via the reconstruction of a suitable constraint; then the quantum dynamics is re-stated in a generic coordinates system and it becomes ...
openaire +2 more sources
On 2D quantum gravity coupled to a σ-model [PDF]
Nuclear Physics B - Proceedings Supplements, 1996 This contribution is a review of the method of isomonodromic quantization of dimensionally reduced gravity. Our approach is based on the complete separation of variables in the isomonodromic sector of the model and the related ``two-time" Hamiltonian structure.
Korotkin, D., Nicolai, H., Samtleben, H.
openaire +4 more sources