395 citations · 878 across the 14 of their papers we have counts for
14 papers
General Relativity versus Dark Matter for rotating galaxies
Yogendra Srivastava, Giorgio Immirzi, John Swain +2
A very general class of axially-symmetric metrics in general relativity (GR) that includes rotations is used to discuss the dynamics of rotationally-supported galaxies. The exact v…
Causal spin foams
Giorgio Immirzi
I discuss how to impose causality on spin-foam models, separating forward and backward propagation, turning a given triangulation to a 'causal set', and giving asymptotically the e…
A note on the spinor construction of Spin Foam amplitudes
Giorgio Immirzi
I discuss the use of spinors in the construction of spin-foam models, in particular the form of the closure and simplicity constraints for triangles that are space-like, i.e. with…
Duality in Fuzzy Sigma Models
A. P. Balachandran, Giorgio Immirzi
Nonlinear `sigma' models in two dimensions have BPS solitons which are solutions of self- and anti-self-duality constraints. In this paper, we find their analogues for fuzzy sigma…
The Fuzzy Ginsparg-Wilson Algebra: A Solution of the Fermion Doubling Problem
A. P. Balachandran, G. Immirzi
The Ginsparg-Wilson algebra is the algebra underlying the Ginsparg-Wilson solution of the fermion doubling problem in lattice gauge theory. The Dirac operator of the fuzzy sphere i…
Fuzzy Nambu-Goldstone Physics
A. P. Balachandran, G. Immirzi
In spacetime dimensions larger than 2, whenever a global symmetry G is spontaneously broken to a subgroup H, and G and H are Lie groups, there are Nambu-Goldstone modes described b…