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We introduce a fully coherent spin network amplitude whose expansion generates all SU(2) spin networks associated with a given graph. We then give an explicit evaluation of this amplitude for an arbitrary graph. We show how this coherent…

General Relativity and Quantum Cosmology · Physics 2015-06-03 Laurent Freidel , Jeff Hnybida

We introduce a new regularization for Thiemann's Hamiltonian constraint. The resulting constraint can generate the 1-4 Pachner moves and is therefore more compatible with the dynamics defined by the spinfoam formalism. We calculate its…

General Relativity and Quantum Cosmology · Physics 2014-11-21 Emanuele Alesci , Carlo Rovelli

We investigate the canonical quantization of 2+1 gravity with {\Lambda} > 0 in the canonical framework of LQG. A natural regularization of the constraints of 2+1 gravity can be defined in terms of the holonomies of A\pm = A \PM…

General Relativity and Quantum Cosmology · Physics 2012-08-15 Karim Noui , Alejandro Perez , Daniele Pranzetti

We consider N=(2,0) backgrounds of IIB supergravity on eight-manifolds M_8 with strict SU(4) structure. We give the explicit solution to the Killing spinor equations as a set of algebraic relations between irreducible su(4) modules of the…

High Energy Physics - Theory · Physics 2013-09-27 Daniël Prins , Dimitrios Tsimpis

The evaluation of relativistic spin networks plays a fundamental role in the Barrett-Crane state sum model of Lorentzian quantum gravity in 4 dimensions. A relativistic spin network is a graph labelled by unitary irreducible representations…

General Relativity and Quantum Cosmology · Physics 2009-11-07 John C. Baez , John W. Barrett

Recently a new model has been proposed to describe free massive spin-2 particles in $D$ dimensions in terms of a non symmetric rank-2 tensor $e_{\mu\nu}$ and a mixed symmetry tensor $B^{\mu[\alpha\beta]}$. The model is invariant under…

High Energy Physics - Theory · Physics 2022-02-02 Alessandro L. R. dos Santos , Denis Dalmazi , Wayne de Paula

Polynomials in Grassmann space can be used to describe all the internal degrees of freedom of spinors, scalars and vectors, that is their spins and charges. It was shown that K\"ahler spinors, which are polynomials of differential forms,…

High Energy Physics - Theory · Physics 2007-05-23 N. Mankoc Borstnik , H. B. Nielsen

The pure braid group \Gamma of a quadruply-punctured Riemann sphere acts on the SL(2,C)-moduli M of the representation variety of such sphere. The points in M are classified into \Gamma-orbits. We show that, in this case, the monodromy…

Algebraic Geometry · Mathematics 2010-12-30 Eugene Z. Xia

Loop Quantum Gravity is now a well established approach to quantum gravity. One of the main challenges still faced by the theory is constructing a consistent dynamics which would lead back to the standard dynamics of the gravitational field…

General Relativity and Quantum Cosmology · Physics 2015-06-03 Enrique F. Borja , Jacobo Díaz-Polo , Laurent Freidel , Iñaki Garay , Etera R. Livine

We provide a holomorphic description of the Hilbert space H(j_1,..,j_n) of SU(2)-invariant tensors (intertwiners) and establish a holomorphically factorized formula for the decomposition of identity in H(j_1,..,j_n). Interestingly, the…

High Energy Physics - Theory · Physics 2015-03-13 Laurent Freidel , Kirill Krasnov , Etera R. Livine

Projected spin network states are the canonical basis of quantum states of geometry for the most recent EPR-FK spinfoam models for quantum gravity. They are functionals of both the Lorentz connection and the time normal field. We analyze in…

General Relativity and Quantum Cosmology · Physics 2014-11-21 Maité Dupuis , Etera R. Livine

Recent works have demonstrated promising performances of neural networks on hyperbolic spaces and symmetric positive definite (SPD) manifolds. These spaces belong to a family of Riemannian manifolds referred to as symmetric spaces of…

Machine Learning · Statistics 2026-01-06 Xuan Son Nguyen , Shuo Yang , Aymeric Histace

We construct an effective cosmological spin-foam model for a (2+1) dimensional spatially flat universe, discretized on a hypercubical lattice, containing both space- and time-like regions. Our starting point is the recently proposed…

General Relativity and Quantum Cosmology · Physics 2025-04-17 Alexander F. Jercher , José Diogo Simão , Sebastian Steinhaus

In a previous work, we have constructed a reparametrization invariant worldsheet action from which one can derive the super-Poincare covariant pure spinor formalism for the superstring at the fully quantum level. The main idea was the…

High Energy Physics - Theory · Physics 2009-11-11 Yuri Aisaka , Yoichi Kazama

In a former paper we proposed a model for the quantization of gravity by working in a bundle $E$ where we realized the Hamilton constraint as the Wheeler-DeWitt equation. However, the corresponding operator only acts in the fibers and not…

General Relativity and Quantum Cosmology · Physics 2018-10-23 Claus Gerhardt

We propose a new holonomy formulation for spin foams, which naturally extends the theory space of lattice gauge theories. This allows current spin foam models to be defined on arbitrary two-complexes as well as to generalize current spin…

General Relativity and Quantum Cosmology · Physics 2013-03-14 Benjamin Bahr , Bianca Dittrich , Frank Hellmann , Wojciech Kaminski

Motivated by potential applications to holography on space-times of positive curvature, and by the successful twistor description of scattering amplitudes, we propose a new dual matrix formulation of N = 4 gauge theory on S(4). The matrix…

High Energy Physics - Theory · Physics 2015-03-19 Jonathan J. Heckman , Herman Verlinde

We derive simplicity constraints for the quantization of general Lorentzian 4-geometries. Our method is based on the correspondence between coherent states and classical bivectors and the minimization of associated uncertainties. For…

General Relativity and Quantum Cosmology · Physics 2011-01-19 Florian Conrady , Jeff Hnybida

Here we have developed a FLEX+DMFT formalism, where the symmetry properties of the system are incorporated by constructing a SO(4) generalization of the conventional fluctuation-exchange approximation (FLEX) coupled self-consistently to the…

Superconductivity · Physics 2019-03-15 Sharareh Sayyad , Naoto Tsuji , Massimo Capone , Hideo Aoki

Tensor networks provide a powerful tool for studying many-body quantum systems, particularly making quantum simulations more efficient. In this article, we construct a tensor network representation of the spin network states, which…

High Energy Physics - Theory · Physics 2024-11-20 Grzegorz Czelusta , Jakub Mielczarek