Results 11 to 20 of about 47,494 (299)
Feynman Propagator for Spin Foam Quantum Gravity [PDF]
Physical Review Letters, 2005 We link the notion causality with the orientation of the 2-complex on which spin foam models are based. We show that all current spin foam models are orientation-independent, pointing out the mathematical structure behind this independence. Using the technology of evolution kernels for quantum fields/particles on Lie groups/homogeneous spaces, we ...
Daniele Oriti
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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
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Operator spin foam models [PDF]
Classical and Quantum Gravity, 2011 19 pages, 11 figures, RevTex4 ...
Bahr, B. +4 more
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Causal Structure in Spin Foams
UniverseThe metric field of general relativity is almost fully determined by its causal structure. Yet, in spin foam models of quantum gravity, the role played by the causal structure is still largely unexplored.
Eugenio Bianchi, Pierre Martin-Dussaud
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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
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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
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, 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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Spin foams with timelike surfaces [PDF]
Classical and Quantum Gravity, 2010 22 pages, no figures; v2: remarks on operator formalism added in discussion; correction: the spin 1/2 irrep of the discrete series does not appear in the Plancherel ...
Florian Conrady
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Causality in spin foam models [PDF]
Physical Review D, 2000 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 structure. This leads us to define a general structure which we call a ``causal spin foam''.
A. Ashtekar +25 more
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MEASUREMENTS AND INFORMATION IN SPIN FOAM MODELS [PDF]
International Journal of Modern Physics A, 2012 In the three-dimensional spin foam model of quantum gravity with a cosmological constant, there exists a set of observables associated with spin network graphs. A set of probabilities is calculated from these observables, and hence the associated Shannon entropy can be defined.
Aczél J. +3 more
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