Results 31 to 40 of about 1,109,861 (332)
, 2023 Spinfoams provide a framework for the dynamics of loop quantum gravity that is manifestly covariant under the full four-dimensional diffeomorphism symmetry group of general relativity. In this way they complete the ideal of three-dimensional diffeomorphism covariance that consistently motivates loop quantum gravity at every step. Specifically, spinfoam
Jonathan Engle, Simone Speziale
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Lorentzian Quantum Cosmology from Effective Spin Foams
UniverseEffective spin foams provide the most computationally efficient spin foam models yet and are therefore ideally suited for applications, e.g., to quantum cosmology.
Bianca Dittrich, José Padua-Argüelles
doaj +3 more sources
Measurements and Information in Spin Foam Models [PDF]
International Journal of Modern Physics A, 2013 We present a problem relating measurements and information theory in spin foam models. In the three dimensional case of quantum gravity we can compute probabilities of spin network graphs and study the behaviour of the Shannon entropy associated to the ...
Aczél J. +3 more
core +4 more sources
Spin Foam Models of Riemannian Quantum Gravity [PDF]
Classical and Quantum Gravity, 2002 Using numerical calculations, we compare three versions of the Barrett-Crane model of 4-dimensional Riemannian quantum gravity. In the version with face and edge amplitudes as described by De Pietri, Freidel, Krasnov, and Rovelli, we show the partition ...
Alekseev A +34 more
core +9 more sources
, 2005 We propose a spin foam model of four-dimensional quantum gravity which is based on the integration of the tetrads in the path integral for the Palatini action of General Relativity. In the Euclidian gravity case we show that the model can be understood as a modification of the Barrett-Crane spin foam model.
Aleksandar Miković
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Loop quantum cosmology and spin foams [PDF]
Physics Letters B, 2009 Loop quantum cosmology (LQC) is used to provide concrete evidence in support of the general paradigm underlying spin foam models (SFMs). Specifically, it is shown that: i) the physical inner product in the timeless framework equals the transition amplitude in the deparameterized theory; ii) this quantity admits a %convergent vertex expansion a la SFMs ...
Abhay Ashtekar +2 more
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Summing bulk quantum numbers with Monte Carlo in spin foam theories [PDF]
Physical Review D, 2023 We introduce a strategy to compute EPRL spin foam amplitudes with many internal faces numerically. We work with sl2cfoam-next, the state-of-the-art framework to numerically evaluate spin foam transition amplitudes.
P. Donà, Pietropaolo Frisoni
semanticscholar +1 more source
A high-performance code for EPRL spin foam amplitudes [PDF]
Classical and quantum gravity, 2021 We present sl2cfoam-next, a high-performance software library for computing Lorentzian EPRL spin foam amplitudes. The library improves on previous codes by many orders of magnitude in single-core performance, can be parallelized on a large number of CPUs
F. Gozzini
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Radiative corrections to the Lorentzian Engle-Pereira-Rovelli-Livine spin foam propagator [PDF]
Physical Review D, 2022 We numerically estimate the divergence of several two-vertex diagrams that contribute to the radiative corrections for the Lorentzian EPRL spin foam propagator.
P. Donà +2 more
semanticscholar +1 more source
Effective spin foam models for Lorentzian quantum gravity [PDF]
, 2021 Making the Lorentzian path integral for quantum gravity well-defined and computable has been a long standing challenge. In this work we adopt the recently proposed effective spin foam models to the Lorentzian case.
Seth K. Asante +2 more
semanticscholar +1 more source