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A covariant spin-foam formulation of quantum gravity has been recently developed, characterized by a kinematics which appears to match well the one of canonical loop quantum gravity. In particular, the geometrical observable giving the area…

General Relativity and Quantum Cosmology · Physics 2014-11-20 You Ding , Carlo Rovelli

We initiate a systematic method to calculate both the finite volume energy levels and form factors from the momentum space finite volume two-point function. By expanding the two point function in the volume we extracted the leading…

High Energy Physics - Theory · Physics 2018-08-15 Zoltán Bajnok , János Balog , Márton Lájer , Chao Wu

We reduce the computation of three point function of three spinning operators with arbitrary polarizations to a statistical mechanics problem via the hexagon formalism. The central building block of these correlation functions is the…

High Energy Physics - Theory · Physics 2022-10-19 Carlos Bercini , Vasco Goncalves , Alexandre Homrich , Pedro Vieira

We describe a theory of quantum gravity which is based on the assumption that the spacetime structure at small distances is given by a piecewise linear (PL) 4-manifold corresponding to a triangulation of a smooth 4-manifold. The fundamental…

General Relativity and Quantum Cosmology · Physics 2018-07-18 Aleksandar Mikovic , Marko Vojinovic

We compute the Schroedinger functional (SF) for the case of pure SU(3) gauge theory at two-loop order in lattice perturbation theory. This allows us to extract the three-loop beta-function in the SF-scheme. These results are required to…

High Energy Physics - Lattice · Physics 2009-10-31 A. Bode , P. Weisz , U. Wolff

In this study, we model a spin-network in loop quantum gravity as a regular tetrahedral lattice, applying lattice physics techniques to study its structure and vertex dynamics. Using the area eigenvalue, $A\propto 8\pi l_P^2$, we derive a…

General Relativity and Quantum Cosmology · Physics 2025-07-22 Noah M. MacKay

We show that the Euclidean and Lorentzian EPRL vertex amplitudes of covariant Loop Quantum Gravity are related through a ``Wick rotation'' of the real Immirzi parameter to purely imaginary values. Our result follows from the simultaneous…

General Relativity and Quantum Cosmology · Physics 2024-02-27 Pietro Dona , Francesco Gozzini , Alessandro Nicotra

We focus on three-dimensional QRLG with the purpose of shedding light on the link between reduced LQG and LQC in four space-time dimensions. Considering homogeneous three-dimensional LQG, the theory simplifies to QRLG. We then implement…

General Relativity and Quantum Cosmology · Physics 2017-07-06 Jakub Bilski , Antonino Marciano

One can try to define the theory of quantum gravity as the sum over geometries. In two dimensions the sum over {\it Euclidean} geometries can be performed constructively by the method of {\it dynamical triangulations}. One can define a {\it…

General Relativity and Quantum Cosmology · Physics 2017-08-23 J. Ambjorn

We investigate the interaction mechanism of pure quantum gravity in Regge discretization. We compute volume-volume and link-link correlation functions. In a preliminary analysis the forces turn out to be of Yukawa type, at least on our…

High Energy Physics - Lattice · Physics 2009-10-22 W. Beirl , H. Markum , J. Riedler

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,…

General Relativity and Quantum Cosmology · Physics 2011-04-01 Benjamin Bahr , Bianca Dittrich , James P. Ryan

We study a two-dimensional conformal field theory coupled to quantum gravity on a disk. Using the continuum Liouville field approach, we compute three-point correlation functions of boundary operators. The structure of momentum…

High Energy Physics - Theory · Physics 2009-10-22 Yoshiaki Tanii , Shun-ichi Yamaguchi

We summarize the basics of the loop representation of quantum gravity and describe the main aspects of the formalism, including its latest developments, in a reorganized and consistent form. Recoupling theory, in its graphical…

General Relativity and Quantum Cosmology · Physics 2011-09-09 Roberto De Pietri , C. Rovelli

I present some preliminary results, obtained in collaboration with C. Bernard and A. Soni, for the lattice evaluation of 2- and 3-point gluon correlation functions in momentum space, with emphasis on the amputated 3-gluon vertex function.…

High Energy Physics - Lattice · Physics 2009-10-22 Claudio Parrinello

Coulomb gauge quantum chromodynamics within the first order functional formalism is considered. The quark contributions to the Dyson-Schwinger equations are derived and one-loop perturbative results for the two-point functions are…

High Energy Physics - Theory · Physics 2009-09-02 C. Popovici , P. Watson , H. Reinhardt

We reconsider the Rovelli-Smolin model of gravity coupled to the Klein-Gordon time field with an eye towards capturing the degrees of freedom of the scalar field lost in the framework in which time is deparametrized by the scalar field.…

General Relativity and Quantum Cosmology · Physics 2016-02-03 Jerzy Lewandowski , Hanno Sahlmann

We introduce a new operator in Loop Quantum Gravity - the 3D curvature operator - related to the 3-dimensional scalar curvature. The construction is based on Regge Calculus. We define it starting from the classical expression of the Regge…

General Relativity and Quantum Cosmology · Physics 2014-06-25 Emanuele Alesci , Mehdi Assanioussi , Jerzy Lewandowski

This paper studies the one-loop expansion of the amplitudes of electromagnetism about flat Euclidean backgrounds bounded by a 3-sphere, recently considered in perturbative quantum cosmology, by using zeta-function regularization. For a…

General Relativity and Quantum Cosmology · Physics 2010-04-06 Giampiero Esposito

Euclidean quantum gravity is studied with renormalisation group methods. Analytical results for a non-trivial ultraviolet fixed point are found for arbitrary dimensions and gauge fixing parameter in the Einstein-Hilbert truncation.…

High Energy Physics - Theory · Physics 2010-04-06 Daniel F. Litim

This paper is twofold. First of all a complete unified picture of $n$-dimensional quantum gravity is proposed in the following sense: In spin foam models of quantum gravity the evaluation of spin networks play a very important role. These…

General Relativity and Quantum Cosmology · Physics 2007-05-23 J. Manuel Garcia-Islas