Results 31 to 40 of about 165,231 (345)
Phenomenology of low quantum gravity scale models [PDF]
Physical Review D, 1999 We study some phenomenological implications of models where the scale of quantum gravity effects lies much below the four-dimensional Planck scale. These models arise from M-theory vacua where either the internal space volume is large or the string coupling is very small.
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An effective matrix model for dynamical end of the world branes in Jackiw-Teitelboim gravity
Journal of High Energy Physics, 2022 We study Jackiw-Teitelboim gravity with dynamical end of the world branes in asymptotically nearly AdS2 spacetimes. We quantize this theory in Lorentz signature, and compute the Euclidean path integral summing over topologies including dynamical branes ...
Ping Gao +2 more
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q -deformed spin foam models of quantum gravity [PDF]
Classical and Quantum Gravity, 2007 We numerically study Barrett-Crane models of Riemannian quantum gravity. We have extended the existing numerical techniques to handle q-deformed models and arbitrary space-time triangulations. We present and interpret expectation values of a few selected observables for each model, including a spin-spin correlation function which gives insight into the
Khavkine, Igor, Christensen, J. Daniel
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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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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
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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
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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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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
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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
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Spectral Flow in 3D Flat Spacetimes [PDF]
, 2017 In this paper we investigate spectral flow symmetry in asymptotically flat spacetimes both from a gravity as well as a putative dual quantum field theory perspective.
Basu, Rudranil +2 more
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