Results 51 to 60 of about 178,240 (316)
Double scaling limits of Dirac ensembles and Liouville quantum gravity [PDF]
Journal of Physics A: Mathematical and Theoretical, 2022 In this paper we study ensembles of finite real spectral triples equipped with a path integral over the space of possible Dirac operators. In the noncommutative geometric setting of spectral triples, Dirac operators take the center stage as a replacement
Hamed Hessam +2 more
semanticscholar +1 more source
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
Towards background independent quantum gravity with tensor models [PDF]
Classical and quantum gravity, 2018 We explore whether the phase diagram of tensor models could feature a pregeometric, discrete and a geometric, continuum phase for the building blocks of space. The latter are associated to rank d tensors of size N.
A. Eichhorn +3 more
semanticscholar +1 more source
Effective dynamics of scalar cosmological perturbations from quantum gravity [PDF]
Journal of Cosmology and Astroparticle Physics, 2021 We derive an effective dynamics for scalar cosmological perturbations from quantum gravity, in the framework of group field theory condensate cosmology. The emergent spacetime picture is obtained from the mean-field hydrodynamic regime of the fundamental
L. Marchetti, D. Oriti
semanticscholar +1 more source
Quantum singularities in a model of f(R) gravity [PDF]
The European Physical Journal C, 2012 The formation of a naked singularity in a model of f(R) gravity having as source a linear electromagnetic field is considered in view of quantum mechanics. Quantum test fields obeying the Klein-Gordon, Dirac and Maxwell equations are used to probe the classical timelike naked singularity developed at r=0.
Gürtuğ, Özay +2 more
openaire +5 more sources
(Loop) quantum gravity and the inflationary scenario [PDF]
, 2015 Quantum gravity, as a fundamental theory of space-time, is expected to reveal how the universe may have started, perhaps during or before an inflationary epoch.
Bojowald, Martin
core +2 more sources
Mass and horizon Dirac observables in effective models of quantum black-to-white hole transition [PDF]
Classical and quantum gravity, 2019 In the past years, black holes and the fate of their singularity have been heavily studied within loop quantum gravity. Effective spacetime descriptions incorporating quantum geometry corrections are provided by the so-called polymer models.
N. Bodendorfer +2 more
semanticscholar +1 more source
Positivity in Lorentzian Barrett–Crane models of quantum gravity [PDF]
Classical and Quantum Gravity, 2006 The Barrett-Crane models of Lorentzian quantum gravity are a family of spin foam models based on the Lorentz group. We show that for various choices of edge and face amplitudes, including the Perez-Rovelli normalization, the amplitude for every triangulated closed 4-manifold is a non-negative real number.
Cherrington, J. Wade +1 more
openaire +2 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
Discrete Lorentzian Quantum Gravity [PDF]
, 2000 Just as for non-abelian gauge theories at strong coupling, discrete lattice methods are a natural tool in the study of non-perturbative quantum gravity. They have to reflect the fact that the geometric degrees of freedom are dynamical, and that therefore
Loll, R.
core +4 more sources