SPIN FOAM AND REGGE CALCULUS

2013 ◽  
Vol 23 ◽  
pp. 363-372
Author(s):  
S. J. GABRIELE GIONTI
Keyword(s):  
Regge Calculus ◽  
Spin Foam ◽  
Closure Constraint ◽  
Unique Spin

Recent results in Local Regge Calculus are confronted with Spin Foam Formalism. Introducing Barrett-Crane Quantization in Local Regge Calculus makes it possible to associate a unique Spin jh with an hinge h, fulfilling one of the requirements of Spin Foam definition. It is shown that inter-twiner terms of Spin Foam can follow from the closure constraint in Local Regge Calculus.

scholarly journals SOME CONSIDERATIONS ON DISCRETE QUANTUM GRAVITY

2012 ◽  
Vol 09 (02) ◽  
pp. 1260013
Author(s):  
S. J. GABRIELE GIONTI
Keyword(s):  
Quantum Gravity ◽  
Regge Calculus ◽  
Spin Foam ◽  
Closure Constraint ◽  
Unique Spin

Recent results in Local Regge Calculus are confronted with Spin-Foam Formalism. Introducing Barrett–Crane Quantization in Local Regge Calculus makes it possible to associate a unique Spin jh with an hinge h, fulfilling one of the requirements of Spin-Foam definition. It is shown that inter-twiner terms of Spin-Foam can follow from the closure constraint in Local Regge Calculus.

scholarly journals Numerical analysis of spin foam dynamics and the flatness problem

2020 ◽  
Vol 102 (10) ◽  
Author(s):  
Pietro Donà ◽  
Francesco Gozzini ◽  
Giorgio Sarno
Keyword(s):  
Numerical Analysis ◽  
Spin Foam ◽  
Flatness Problem

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 A spin foam model without bubble divergences

2001 ◽  
Vol 599 (1-2) ◽  
pp. 255-282 ◽  
Author(s):  
Alejandro Perez ◽  
Carlo Rovelli
Keyword(s):  
Foam Model ◽  
Spin Foam Model ◽  
Spin Foam

scholarly journals Regge calculus in the canonical form

1995 ◽  
Vol 27 (6) ◽  
pp. 583-603 ◽  
Author(s):  
V. Khatsymovsky
Keyword(s):  
Canonical Form ◽  
Regge Calculus

Magnetic Anisotropy in Electrodeposited CO Films and spin-valves on Gaas Substrates

1999 ◽  
Vol 562 ◽  
Author(s):  
K. Attenborough ◽  
M. Cerisier ◽  
H. Boeve ◽  
J. De Boeck ◽  
G. Borghs ◽  
...  
Keyword(s):  
Magnetic Anisotropy ◽  
Buffer Layer ◽  
Structural Properties ◽  
Easy Axis ◽  
Spin Valve ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cu Films ◽  
Gaas Substrates ◽  
Unique Spin

ABSTRACTWe have studied the magnetic and structural properties of thin electrodeposited Co and Cu layers grown directly onto (100) n-GaAs and have investigated the influence of a buffer layer. A dominant fourfold anisotropy with a uniaxial contribution is observed in 10 nm Co electrodeposited films on GaAs. An easy axis is observed in the [001] GaAs direction with two hard axes of differing coercivities parallel to the [011] and [011] directions. For thicker films the easy axes in the [001] direction becomes less pronounced and the fourfold anisotropy becomes less dominant. Co films of similar thicknesses deposited onto an electrodeposited Cu buffer layer were nearly isotropic. From X-ray diffraction 21 nm Co layers on GaAs were found to be hcp with the c-axis tending to be in the plane of the film. The anisotropy is ascribed to the Co/GaAs interface and is held responsible for the unique spin-valve properties seen recently in electrodeposited Co/Cu films.

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