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The Spin-Foam Approach to Quantum Gravity [PDF]
Living Reviews in Relativity, 2013 This article reviews the present status of the spin-foam approach to the quantization of gravity. Special attention is payed to the pedagogical presentation of the recently-introduced new models for four-dimensional quantum gravity.
Alejandro Perez
exaly +10 more sources
Spin Foams and Canonical Quantization [PDF]
Symmetry, Integrability and Geometry: Methods and Applications, 2012 This review is devoted to the analysis of the mutual consistency of the spin foam and canonical loop quantizations in three and four spacetime dimensions.
Sergei Alexandrov +2 more
doaj +8 more sources
Positivity of Spin Foam Amplitudes [PDF]
Classical and Quantum Gravity, 2001 The amplitude for a spin foam in the Barrett-Crane model of Riemannian quantum gravity is given as a product over its vertices, edges and faces, with one factor of the Riemannian 10j symbols appearing for each vertex, and simpler factors for the edges ...
Ambjørn J +20 more
core +8 more sources
Causality in Spin Foam Models [PDF]
Physical Review D, 1999 We compute Teitelboim's causal propagator in the context of canonical loop quantum gravity. For the Lorentzian signature, we find that the resultant power series can be expressed as a sum over branched, colored two-surfaces with an intrinsic causal ...
A. Ashtekar +25 more
core +4 more sources
4-dimensional Spin-foam Model with Quantum Lorentz Group [PDF]
, 2011 We study the quantum group deformation of the Lorentzian EPRL spin-foam model. The construction uses the harmonic analysis on the quantum Lorentz group.
Han, Muxin
core +4 more sources
Group field theories for all loop quantum gravity
New Journal of Physics, 2015 Group field theories represent a second quantized reformulation of the loop quantum gravity state space and a completion of the spin foam formalism. States of the canonical theory, in the traditional continuum setting, have support on graphs of arbitrary
Daniele Oriti +2 more
doaj +2 more sources
Four-Dimensional Spin Foam Perturbation Theory [PDF]
Symmetry, Integrability and Geometry: Methods and Applications, 2011 We define a four-dimensional spin-foam perturbation theory for the BF-theory with a B∧B potential term defined for a compact semi-simple Lie group G on a compact orientable 4-manifold M.
João Faria Martins, Aleksandar Mikovic
doaj +5 more sources
Optimizing Osseodensification Drilling for Dental Implant Placement: An In Vitro Study [PDF]
Clinical and Experimental Dental ResearchObjectives This study aims to optimize the parameters of osseodensification drilling (OD) to improve the primary stability of dental implants in low‐density bone.
Xingru Tao +5 more
doaj +2 more sources
Enhancing Tennis Practice: Sensor Fusion and Pose Estimation with a Smart Tennis Ball [PDF]
SensorsThis article demonstrates the integration of sensor fusion for pose estimation and data collection in tennis balls, aiming to create a smaller, less intrusive form factor for use in progressive learning during tennis practice.
Yu Kit Foo, Xi Li, Rami Ghannam
doaj +2 more sources
Ultrasonic-assisted Fenton reaction inducing surface reconstruction endows nickel/iron-layered double hydroxide with efficient water and organics electrooxidation [PDF]
Ultrasonics SonochemistryNickel/iron-layered double hydroxide (NiFe-LDH) tends to undergo an electrochemically induced surface reconstruction during the water oxidation in alkaline, which will consume excess electric energy to overcome the reconstruction thermodynamic barrier ...
Shanfu Sun +9 more
doaj +2 more sources