scholarly journals Spin foam models and the classical action principle

1998 ◽  
Vol 2 (6) ◽  
pp. 1183-1247 ◽  
Author(s):  
Laurent Freidel ◽  
Kirill Krasnov
Keyword(s):  
Action Principle ◽  
Classical Action ◽  
Spin Foam Models ◽  
Spin Foam

scholarly journals MEASUREMENTS AND INFORMATION IN SPIN FOAM MODELS

2012 ◽  
Vol 27 (28) ◽  
pp. 1250164
Author(s):  
J. MANUEL GARCÍA-ISLAS
Keyword(s):  
Information Theory ◽  
Quantum Gravity ◽  
Cosmological Constant ◽  
Shannon Entropy ◽  
Three Dimensional ◽  
Spin Network ◽  
Spin Foam Models ◽  
Foam Model ◽  
Spin Foam Model ◽  
Spin Foam

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. We present the Shannon entropy associated with these observables and find some interesting bounded inequalities. The problem relates measurements, entropy and information theory in a simple way which we explain.

scholarly journals Renormalization of symmetry restricted spin foam models with curvature in the asymptotic regime

2018 ◽  
Vol 98 (10) ◽  
Author(s):  
Benjamin Bahr ◽  
Giovanni Rabuffo ◽  
Sebastian Steinhaus
Keyword(s):  
Asymptotic Regime ◽  
Spin Foam Models ◽  
Spin Foam

scholarly journals Coarse graining in spin foam models

2003 ◽  
Vol 20 (5) ◽  
pp. 777-799 ◽  
Author(s):  
Fotini Markopoulou
Keyword(s):  
Coarse Graining ◽  
Spin Foam Models ◽  
Spin Foam

scholarly journals Spin foam models and the Duflo map

2019 ◽  
Vol 37 (1) ◽  
pp. 015010 ◽  
Author(s):  
Marco Finocchiaro ◽  
Daniele Oriti
Keyword(s):  
Spin Foam Models ◽  
Spin Foam ◽  
Duflo Map

scholarly journals The Hessian in Spin Foam Models

2019 ◽  
Vol 20 (12) ◽  
pp. 3927-3953
Author(s):  
Wojciech Kamiński ◽  
Hanno Sahlmann
Keyword(s):  
Asymptotic Analysis ◽  
Stationary Points ◽  
Spin Foam Models ◽  
Spin Foam

Abstract We fill one of the remaining gaps in the asymptotic analysis of the vertex amplitudes of the Engle–Pereira–Rovelli–Livine (EPRL) spin foam models: We show that the Hessian is nondegenerate for the stationary points that corresponds to geometric nondegenerate 4 simplices. Our analysis covers the case when all faces are spacelike.

scholarly journals Timelike surfaces in Lorentz covariant loop gravity and spin foam models

2005 ◽  
Vol 22 (17) ◽  
pp. 3491-3509 ◽  
Author(s):  
Sergei Alexandrov ◽  
Zoltán Kádár
Keyword(s):  
Spin Foam Models ◽  
Spin Foam ◽  
Loop Gravity

scholarly journals Quantum Field Theory of Open Spin Networks and New Spin Foam Models

2003 ◽  
Vol 18 (supp02) ◽  
pp. 83-96 ◽  
Author(s):  
A. Miković
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Vector Bundles ◽  
Tensor Category ◽  
Quantum Field Theories ◽  
Quantum Field ◽  
Spin Networks ◽  
Spin Foam Models ◽  
Topological Quantum ◽  
Spin Foam

We describe how a spin-foam state sum model can be reformulated as a quantum field theory of spin networks, such that the Feynman diagrams of that field theory are the spin-foam amplitudes. In the case of open spin networks, we obtain a new type of state-sum models, which we call the matter spin foam models. In this type of state-sum models, one labels both the faces and the edges of the dual two-complex for a manifold triangulation with the simple objects from a tensor category. In the case of Lie groups, such a model corresponds to a quantization of a theory whose fields are the principal bundle connection and the sections of the associated vector bundles. We briefly discuss the relevance of the matter spin foam models for quantum gravity and for topological quantum field theories.

scholarly journals TIME MACHINES: THE PRINCIPLE OF SELF-CONSISTENCY AS A CONSEQUENCE OF THE PRINCIPLE OF MINIMAL ACTION

1995 ◽  
Vol 04 (05) ◽  
pp. 557-580 ◽  
Author(s):  
A. CARLINI ◽  
V.P. FROLOV ◽  
M.B. MENSKY ◽  
I.D. NOVIKOV ◽  
H.H. SOLENG
Keyword(s):  
Interaction Potential ◽  
Hard Sphere ◽  
Action Principle ◽  
Natural Consequence ◽  
Classical Action ◽  
Minimal Action ◽  
Interacting Particle ◽  
Self Consistent ◽  
Time Machines ◽  
Self Consistency

We consider the action principle to derive the classical, nonrelativistic motion of a self-interacting particle in a 4D Lorentzian spacetime containing a wormhole and which allows the existence of closed time-like curves. For the case of a “hard-sphere” self-interaction potential we show that the only possible trajectories (for a particle with fixed initial and final positions and which traverses the wormhole once) minimizing the classical action are those which are globally self-consistent, and that the “principle of self-consistency” (originally introduced by Novikov) is thus a natural consequence of the “principle of minimal action.”

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