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MHV diagrams give an efficient Feynman diagram-like formalism for calculating gauge theory scattering amplitudes on momentum space. Although they arise as the Feynman diagrams from an action on twistor space in an axial gauge, the main…

High Energy Physics - Theory · Physics 2015-05-27 Tim Adamo , Lionel Mason

It is a commonplace that any theory can be written in any coordinates via tensor calculus. But it is claimed that spinors as such cannot be represented in coordinates in a curved space-time. What general covariance means for theories with…

General Relativity and Quantum Cosmology · Physics 2016-03-21 J. Brian Pitts

The first computation of a spin foam dynamics that provides a test of the quantum equations of motions of gravity is presented. Specifically, a triangulation that includes an inner edge is treated. The computation leverages the recently…

General Relativity and Quantum Cosmology · Physics 2021-07-07 Seth K. Asante , Bianca Dittrich , Hal M. Haggard

The spinfoam framework is a proposal for a regularized path integral for quantum gravity. Spinfoams define quantum space-time structures describing the evolution in time of the spin network states for quantum geometry derived from Loop…

General Relativity and Quantum Cosmology · Physics 2015-03-19 Maité Dupuis

We study the (generalized) transition probability spaces, in the sense of Mielnik and Cantoni, for spacetime quantum states in loop quantum gravity. First, we show that loop quantum gravity admits the structures of transition probability…

General Relativity and Quantum Cosmology · Physics 2018-03-15 Xiao-Kan Guo

We show that loop gravity can equally well be formulated in in terms of spinorial variables (instead of the group variables which are commonly used), which have recently been shown to provide a direct link between spin network states and…

General Relativity and Quantum Cosmology · Physics 2015-05-30 Etera R. Livine , Johannes Tambornino

In this work, it is demonstrated how the kinematical Hilbert space of Loop Quantum Gravity (LQG) can be inferred from the configuration space of BF theories via the imposition of the Hamiltonian constraints. In particular, it is outlined…

General Relativity and Quantum Cosmology · Physics 2015-05-20 Francesco Cianfrani

We introduce a notion of twisted pure spinor in order to characterize, in a unified way, all the special Riemannian holonomy groups just as a classical pure spinor characterizes the special K\"ahler holonomy. Motivated by certain curvature…

Differential Geometry · Mathematics 2019-09-24 Rafael Herrera , Noemi Santana

Canonical gravity can be formulated by means of a densitized dreibein together with an SU(2) connection. These so-called Ashtekar variables are the fundamental quantities, loop quantum gravity is resting on. In this paper we review these…

Mathematical Physics · Physics 2011-12-07 Christian Fleischhack , Philipp Levermann

Spin Foam and Loop approaches to Quantum Gravity reformulate Einstein's theory of relativity in terms of connection variables. The metric properties are encoded in face bivectors/conjugate fluxes that are required to satisfy certain…

General Relativity and Quantum Cosmology · Physics 2019-05-17 Vadim Belov

The study of toy models in loop quantum gravity (LQG), defined as truncations of the full theory, is relevant to both the development of the LQG phenomenology, in cosmology and astrophysics, and the progress towards the resolution of the…

General Relativity and Quantum Cosmology · Physics 2022-07-13 Eneko Aranguren , Iñaki Garay , Etera R. Livine

We explain how twistor theory represents the self-dual sector of four dimensional gravity in terms of the loop group of Poisson diffeomorphisms of the plane via Penrose's non-linear graviton construction. The symmetries of the self-dual…

High Energy Physics - Theory · Physics 2022-03-09 Tim Adamo , Lionel Mason , Atul Sharma

In Loop Quantum Gravity, tremendous progress has been made using the Ashtekar-Barbero variables. These variables, defined in a gauge-fixing of the theory, correspond to a parametrization of the solutions of the so-called simplicity…

General Relativity and Quantum Cosmology · Physics 2018-05-09 Christoph Charles

Spin foam models are an attempt for a covariant, or path integral formulation of canonical loop quantum gravity. The construction of such models usually rely on the Plebanski formulation of general relativity as a constrained BF theory and…

General Relativity and Quantum Cosmology · Physics 2015-05-13 Aristide Baratin , Cecilia Flori , Thomas Thiemann

In this paper, we study the discrete classical phase space of loop gravity, which is expressed in terms of the holonomy-flux variables, and show how it is related to the continuous phase space of general relativity. In particular, we prove…

General Relativity and Quantum Cosmology · Physics 2013-04-04 Laurent Freidel , Marc Geiller , Jonathan Ziprick

In this work, we analyze the possibilities of certain gauge transformations regarding some specific spinorial dual structures. To this end, we define a general structure, which can be expressed in terms of discrete symmetry operators…

High Energy Physics - Theory · Physics 2025-01-10 R. J. Bueno Rogerio , G. B. de Gracia

We propose an unified approach to loop quantum gravity and Fedosov quantization of gravity following the geometry of double spacetime fibrations and their quantum deformations. There are considered pseudo-Riemannian manifolds enabled with…

General Relativity and Quantum Cosmology · Physics 2009-11-21 Sergiu I. Vacaru

We define a theory of gravity by constructing a gravitational holonomy operator in twistor space. The theory is a gauge theory whose Chan-Paton factor is given by a trace over elements of Poincar\'{e} algebra and Iwahori-Hecke algebra. This…

High Energy Physics - Theory · Physics 2010-05-27 Yasuhiro Abe

We revise the classical continuum formulation behind the Spin Foam approach to the quantization of gravity. Based on the recent applications of the current EPRL-FK model beyond triangulations, we identify the tension with the implementation…

General Relativity and Quantum Cosmology · Physics 2018-11-15 Vadim Belov

We consider quantum transition amplitudes, partition functions and observables for 3D spin foam models within $SU(2)$ quantum group deformation symmetry, where the deformation parameter is a complex fifth root of unity. By considering…

High Energy Physics - Theory · Physics 2022-01-13 Marcelo Amaral , Raymond Aschheim , Klee Irwin