Results 11 to 20 of about 47,027 (304)

Operator Spin Foam Models [PDF]

Classical and Quantum Gravity, 2010
The goal of this paper is to introduce a systematic approach to spin foams. We define operator spin foams, that is foams labelled by group representations and operators, as the main tool.
Alesci E Bianchi E Magliaro E Perini C, Alesci E Bianchi E Rovelli C, Ashtekar A, Ashtekar A, Baez J C, Bahr B, Bahr B Dittrich B, Baratin A Flori C Thiemann T, Barrett J, Barrett J, Benjamin Bahr, Bianchi E, Bonzom V, Conrady F, Dittrich B Ryan J P, Engle J Han M Thiemann T, Frank Hellmann, Freidel L, Freidel L, Geloun J B Gurau R Rivasseau V, Han M Thiemann T, Han M Thiemann T, Jerzy Lewandowski, Kamiński W, Kamiński W, Kamiński W, Krajewski T Magnen J Rivasseau V Tanasa A Vitale P, Livine E R, Mamone D Rovelli C, Marcin Kisielowski, Perez A, Pfeiffer H, Reisenberger M P, Wojciech Kamiński   +33 more
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Spin Foams and Noncommutative Geometry [PDF]

Classical and Quantum Gravity, 2010
We extend the formalism of embedded spin networks and spin foams to include topological data that encode the underlying three-manifold or four-manifold as a branched cover.
Aastrup J, Aastrup J, Aastrup J Grimstrup J M, Aastrup J Grimstrup J M Paschke M, Aastrup J Grimstrup J M Paschke M, Aastrup J Grimstrup J M Paschke M Nest R, Ahmad Zainy al-Yasry, Baez J C, Bobtcheva I Piergallini R, Bratteli O, Bratteli O, Brodzki J, Chamseddine A H, Connes A, Connes A, Domenic Denicola, Duston C, Engle J, Fox R H, Hamber H W, Kauffman L H, Kinoshita S, Matilde Marcolli, Penrose R, Ponzano G, Prasolov V V, Rovelli C, Schleich K, Stillwell J, Zainy al-Yasry A   +29 more
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Causal Structure in Spin Foams

Universe
The 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
doaj   +3 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   +6 more sources

Spin-Foam Models and the Physical Scalar Product [PDF]

Physical Review D, 2008
This paper aims at clarifying the link between Loop Quantum Gravity and Spin-Foam models in four dimensions. Starting from the canonical framework, we construct an operator P acting on the space of cylindrical functions Cyl($\Gamma$), where $\Gamma$ is ...
Alesci, Emanuele, Noui, Karim, Sardelli, Francesco   +2 more
core   +5 more sources

The Holst spin foam model via cubulations [PDF]

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, Cecilia Flori, Thomas Thiemann   +2 more
doaj   +6 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, A. Ashtekar, A. Ashtekar, C. Rovelli, C. Rovelli, C. Rovelli, C. Rovelli, C. Rovelli, C. Teitelboim, C. Teitelboim, F. Barbero G., F. Barbero G., F. Markopoulou, J. Ambjørn, J.C. Baez, J.W. Barrett, L. Bombelli, L. Smolin, M. Reisenberger, R. Borissov, R. Borissov, R. De Pietri, R. Laflamme, Sameer Gupta, T. Thiemann, T. Thiemann   +25 more
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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., Bose R. C., J. MANUEL GARCÍA-ISLAS, Piunikhin S. A.   +3 more
core   +5 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

Spin foam diagrammatics and topological invariance [PDF]

Classical and Quantum Gravity, 2002
20 pages, latex with AMS macros and eps ...
Florian Girelli, Robert Oeckl, Alejandro Pérez   +2 more
openalex   +5 more sources