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In this article we further investigate the construction of graph coherent states, first introduced in [1], in the context of loop quantum gravity. We specifically investigate the possibility of defining a family of graph coherent states…

General Relativity and Quantum Cosmology · Physics 2020-07-01 Mehdi Assanioussi

In the weak field expansion of euclidean quantum gravity, an analysis of the Wilson loops in terms of the gauge group, $SO(4)$, shows that the correspondent statistical system does not develope any configuration with localized curvature at…

High Energy Physics - Theory · Physics 2009-10-22 Giovanni Modanese

Loop Quantum Gravity faces challenges in constructing a well-defined Hamiltonian constraint and understanding the quantum notion of time. In this paper these issues are studied by quantizing the $U(1)^3$ model, a simplified system…

General Relativity and Quantum Cosmology · Physics 2024-12-02 Sepideh Bakhoda , Yongge Ma

We use the recently introduced U(N) framework for loop quantum gravity to study the dynamics of spin network states on the simplest class of graphs: two vertices linked with an arbitrary number N of edges. Such graphs represent two regions,…

General Relativity and Quantum Cosmology · Physics 2011-03-28 Enrique F. Borja , Jacobo Diaz-Polo , Iñaki Garay , Etera R. Livine

A Wilson loop is defined, in 4-D pure Einstein gravity, as the trace of the holonomy of the Christoffel connection or of the spin connection, and its invariance under the symmetry transformations of the action is showed (diffeomorphisms and…

High Energy Physics - Theory · Physics 2009-10-22 Giovanni Modanese

The implementation of the dynamics in loop quantum gravity (LQG) is still an open problem. Here, we discuss a tentative dynamics for the simplest class of graphs in LQG: Two vertices linked with an arbitrary number of edges. We find an…

General Relativity and Quantum Cosmology · Physics 2015-05-30 Enrique F. Borja , Jacobo Diaz-Polo , Laurent Freidel , Iñaki Garay , Etera R. Livine

We develop the quantization of unimodular gravity in the Plebanski and Ashtekar formulations and show that the quantum effective action defined by a formal path integral is unimodular. This means that the effective quantum geometry does not…

High Energy Physics - Theory · Physics 2013-05-29 Lee Smolin

The Hamiltonian formulation of scalar-tensor theories of gravity is derived from their Lagrangian formulation by Hamiltonian analysis. The Hamiltonian formalism marks off two sectors of the theories by the coupling parameter $\omega(\phi)$.…

General Relativity and Quantum Cosmology · Physics 2015-05-28 Xiangdong Zhang , Yongge Ma

This is the second paper in the series to introduce a graphical method to loop quantum gravity. We employ the graphical method as a powerful tool to calculate the actions of the Euclidean Hamiltonian constraint operator and the so-called…

General Relativity and Quantum Cosmology · Physics 2016-02-25 Jinsong Yang , Yongge Ma

This work is devoted to a rigorous analysis of the weak coupling limit (WCL) for the reduced dynamics of an open infinite-dimensional quantum system interacting with electromagnetic field or a reservoir formed by Fermi or Bose particles in…

Mathematical Physics · Physics 2025-05-14 Ilya Lopatin , Alexander Pechen

We start with the Hamiltonian formulation of the first order action of pure gravity with a full $\mathfrak{sl}(2,\mathbb C)$ internal gauge symmetry. We make a partial gauge-fixing which reduces $\mathfrak{sl}(2,\mathbb C)$ to its…

General Relativity and Quantum Cosmology · Physics 2017-06-28 Hongguang Liu , Karim Noui

In loop quantum cosmology, one has to make a choice of SU(2) irreducible representation in which to compute holonomies and regularize the curvature of the connection. The systematic choice made in the literature is to work in the…

General Relativity and Quantum Cosmology · Physics 2017-04-26 Jibril Ben Achour , Suddhasattwa Brahma , Marc Geiller

Using a new procedure based on Kummer's Confluent Hypergeometric Functions, we investigate the question of singularity avoidance in loop quantum gravity (LQG) in the context of U$(1)^3$ complexifier coherent states and compare obtained…

General Relativity and Quantum Cosmology · Physics 2021-09-16 Kristina Giesel , David Winnekens

A reduced dynamical model is derived which describes the interaction of weak inertia-gravity waves with nonlinear vortical motion in the context of rotating shallow-water flow. The formal scaling assumptions are (i) that there is a…

chao-dyn · Physics 2009-10-28 Caroline Nore , Theodore G. Shepherd

A gauge theory of quantum gravity is formulated, in which an internal, field dependent metric is introduced which non-linearly realizes the gauge fields on the non-compact group $SL(2,C)$, while linearly realizing them on $SU(2)$.…

General Relativity and Quantum Cosmology · Physics 2007-05-23 J. W. Moffat

A new kind of gauge theory is introduced, where the minimal coupling and corresponding covariant derivatives are defined in the space of functions pertaining to the functional Schroedinger picture of a given field theory. While, for…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Hans-Thomas Elze

The Weak Gravity Conjecture states that in any consistent theory of quantum gravity in the landscape of string theory, the repulsive force mediated by a U(1) gauge field must be stronger than the attractive force of gravity. In this work,…

High Energy Physics - Theory · Physics 2025-03-13 Tommaso Antonelli , Xavier Calmet

The implementation of the dynamics in Loop Quantum Gravity (LQG) is still an open problem. Here, we discuss a tentative dynamics for the simplest class of graphs in LQG: Two vertices linked with an arbitrary number of edges. We use the…

General Relativity and Quantum Cosmology · Physics 2015-05-20 Enrique F. Borja , Jacobo Díaz-Polo , Iñaki Garay , Etera R. Livine

As modified gravity theories, the 4-dimensional metric $f(R)$ theories are cast into connection dynamical formalism with real $su(2)$-connections as configuration variables. This formalism enables us to extend the non-perturbative loop…

General Relativity and Quantum Cosmology · Physics 2015-05-28 Xiangdong Zhang , Yongge Ma

It was recently shown that tunneling wavefunction proposal is consistent with loop quantum geometry corrections including both holonomy and inverse scale factor corrections in the gravitational part of a spatially closed isotropic model…

General Relativity and Quantum Cosmology · Physics 2023-04-17 Meysam Motaharfar , Parampreet Singh