Results 61 to 70 of about 173,760 (383)
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
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Gravity as an ensemble and the moment problem
Journal of High Energy Physics, 2021 If a bulk gravitational path integral can be identified with an average of partition functions over an ensemble of boundary quantum theories, then a corresponding moment problem can be solved. We review existence and uniqueness criteria for the Stieltjes
Oliver Janssen +2 more
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Emergent cosmology from quantum gravity in the Lorentzian Barrett-Crane tensorial group field theory model [PDF]
Journal of Cosmology and Astroparticle Physics, 2021 We study the cosmological sector of the Lorentzian Barrett-Crane (BC) model coupled to a free massless scalar field in its Group Field Theory (GFT) formulation, corresponding to the mean-field hydrodynamics obtained from coherent condensate states.
Alexander F. Jercher +2 more
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Solving puzzles in deformed JT gravity: phase transitions and non-perturbative effects
Journal of High Energy Physics, 2021 Recent work has shown that certain deformations of the scalar potential in Jackiw-Teitelboim gravity can be written as double-scaled matrix models. However, some of the deformations exhibit an apparent breakdown of unitarity in the form of a negative ...
Clifford V. Johnson, Felipe Rosso
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Complex, Lorentzian, and Euclidean simplicial quantum gravity: numerical methods and physical prospects [PDF]
Classical and quantum gravity, 2021 Evaluating gravitational path integrals in the Lorentzian has been a long-standing challenge due to the numerical sign problem. We show that this challenge can be overcome in simplicial quantum gravity.
Ding (贾 Jia 丁)
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A model of quantum collapse induced by gravity [PDF]
The European Physical Journal D, 2020 Version pubished in ...
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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
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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
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Spin foam models for quantum gravity [PDF]
Classical and Quantum Gravity, 2003 In this article we review the present status of the spin foam formulation of non-perturbative (background independent) quantum gravity. The article is divided in two parts. In the first part we present a general introduction to the main ideas emphasizing their motivations from various perspectives.
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Contextual extensions of quantum gravity models [PDF]
International Journal of Geometric Methods in Modern Physics, 2021 We present a simple way of incorporating the structure of contextual extensions into quantum gravity models. The contextual extensions of [Formula: see text]-algebras, originally proposed for contextual hidden variables, are generalized to the cones indexed by the contexts and their limit in a category.
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