Results 21 to 30 of about 1,109,861 (332)
Asymptotic analysis of spin foam amplitude with timelike triangles [PDF]
Physical Review D, 2018 The large-j asymptotic behavior of the four-dimensional spin foam amplitude is investigated for the extended spin foam model (Conrady-Hnybida extension) on a simplicial complex.
Hongguang Liu, Muxin Han
semanticscholar +3 more sources
A finiteness bound for the EPRL/FK spin foam model [PDF]
, 2013 We show that the EPRL/FK spin foam model of quantum gravity has an absolutely convergent partition function if the vertex amplitude is divided by an appropriate power $p$ of the product of dimensions of the vertex spins.
Aleksandar Miković, Marko Vojinović
openalex +3 more sources
Toward a spin foam model description of black hole entropy [PDF]
, 2008 We propose a way to describe the origin of black hole entropy in the spin foam models of quantum gravity. This stimulates a new way to study the relation of spin foam models and loop quantum gravity.Comment: 5 pages, 1 ...
J Manuel García-Islas
openalex +3 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
, 2016 I discuss how to impose causality on spin-foam models, separating forward and backward propagation, turning a given triangulation to a 'causal set', and giving asymptotically the exponential of the Regge action, not a cosine. I show the equivalence of the prescriptions which have been proposed to achieve this.
Giorgio Immirzi
openalex +3 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 +2 more sources
Spin Foam Perturbation Theory [PDF]
, 1999 We study perturbation theory for spin foam models on triangulated manifolds. Starting with any model of this sort, we consider an arbitrary perturbation of the vertex amplitudes, and write the evolution operators of the perturbed model as convergent ...
Baez, John C.
core +5 more sources
The Holst spin foam model via cubulations
New Journal of Physics, 2012 Spin foam models are an attempt at a covariant or path integral formulation of canonical loop quantum gravity. The construction of such models usually relies on the Plebanski formulation of general relativity as a constrained BF theory and is based on ...
Aristide Baratin +2 more
doaj +4 more sources
The Construction of Spin Foam Vertex Amplitudes [PDF]
Symmetry, Integrability and Geometry: Methods and Applications, 2013 Spin foam vertex amplitudes are the key ingredient of spin foam models for quantum gravity. These fall into the realm of discretized path integral, and can be seen as generalized lattice gauge theories.
Eugenio Bianchi, Frank Hellmann
doaj +5 more sources
Spin foams as Feynman diagrams [PDF]
2001: A Relativistic Spacetime Odyssey, 2000 It has been recently shown that a certain non-topological spin foam model can be obtained from the Feynman expansion of a field theory over a group. The field theory defines a natural ``sum over triangulations'', which removes the cut off on the number of degrees of freedom and restores full covariance.
Michael Reisenberger, Carlo Rovelli
openalex +3 more sources