scholarly journals Invited review: The new spin foam models and quantum gravity

2012 ◽  
Vol 4 (0) ◽  
Author(s):  
Alejandro Perez
2012 ◽  
Vol 27 (28) ◽  
pp. 1250164
Author(s):  
J. MANUEL GARCÍA-ISLAS

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.


2013 ◽  
Vol 2013 ◽  
pp. 1-28 ◽  
Author(s):  
Benjamin Bahr ◽  
Bianca Dittrich ◽  
James P. Ryan

Spin foam models, loop quantum gravity, and group field theory are discussed as quantum gravity candidate theories and usually involve a continuous Lie group. We advocate here to consider quantum gravity-inspired models with finite groups, firstly as a test bed for the full theory and secondly as a class of new lattice theories possibly featuring an analogue diffeomorphism symmetry. To make these notes accessible to readers outside the quantum gravity community, we provide an introduction to some essential concepts in the loop quantum gravity, spin foam, and group field theory approach and point out the many connections to the lattice field theory and the condensed-matter systems.


2009 ◽  
Vol 24 (15) ◽  
pp. 2776-2782 ◽  
Author(s):  
KIRILL KRASNOV

Spin foam models of quantum gravity are based on Plebanski's formulation of general relativity as a constrained BF theory. We give an alternative formulation of gravity as BF theory plus a certain potential term for the B-field. When the potential is taken to be infinitely steep one recovers general relativity. For a generic potential the theory still describes gravity in that it propagates just two graviton polarizations. The arising class of theories is of the type amenable to spin foam quantization methods, and, we argue, may allow one to come to terms with renormalization in the spin foam context.


2003 ◽  
Vol 20 (6) ◽  
pp. R43-R104 ◽  
Author(s):  
Alejandro Perez

Author(s):  
Seth Kurankyi Asante ◽  
Bianca Dittrich ◽  
José Padua-Argüelles

2002 ◽  
Vol 19 (18) ◽  
pp. 4627-4648 ◽  
Author(s):  
John C Baez ◽  
J Daniel Christensen ◽  
Thomas R Halford ◽  
David C Tsang

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