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We demonstrate a tensor renormalization group (TRG) calculation for a two-dimensional Lorentzian model of quantum Regge calculus (QRC). This model is expressed in terms of a tensor network by discretizing the continuous edge lengths of…

High Energy Physics - Theory · Physics 2022-11-24 Yoshiyasu Ito , Daisuke Kadoh , Yuki Sato

A low-energy perturbation theory is developed from the nonperturbative framework of covariant Loop Quantum Gravity (LQG) by employing the background field method. The resulting perturbation theory is a 2-parameter expansion in the…

General Relativity and Quantum Cosmology · Physics 2014-06-17 Muxin Han

A linear vector model of gravitation is introduced in the context of quantum physics as a generalization of electromagnetism. The gravitoelectromagnetic gauge symmetry corresponds to a hyperbolic unitary extension of the usual complex phase…

General Relativity and Quantum Cosmology · Physics 2014-07-01 S. Ulrych

We consider a class of Lorentz gauge gravity theories within Riemann-Cartan geometry which admits a topological phase in the gravitational sector. The dynamic content of such theories is determined only by the contortion part of the Lorentz…

General Relativity and Quantum Cosmology · Physics 2012-04-12 D. G. Pak , Youngman Kim , Takuya Tsukioka

One of the qualitatively distinct and robust implication of Loop Quantum Gravity (LQG) is the underlying discrete structure. In the cosmological context elucidated by Loop Quantum Cosmology (LQC), this is manifested by the Hamiltonian…

General Relativity and Quantum Cosmology · Physics 2009-11-11 Kinjal Banerjee , Ghanashyam Date

This is a contribution to the MG9 session QG1-a. A new quantum representation for the Lorentzian gravity is created from the Pullin vaccum by the operators assigned to 2-complexes. The representation uses the original, spinorial Ashtekar…

General Relativity and Quantum Cosmology · Physics 2017-08-23 Marcin Bobieński , Jerzy Lewandowski , Mariusz Mroczek

We develop a unified framework to compute band-geometric quantities in multiband systems whose low-energy Hamiltonians realize arbitrary $SU(2)$ representations. Exploiting the presence of a quantization axis, we use the Wigner--Eckart…

Mesoscale and Nanoscale Physics · Physics 2026-02-18 Rhonald Burgos Atencia

Taking Euclidean signature space-time with its local Spin(4)=SU(2)xSU(2) group of space-time symmetries as fundamental, one can consistently gauge one SU(2) factor to get a chiral spin connection formulation of general relativity, the other…

High Energy Physics - Theory · Physics 2021-10-18 Peter Woit

We recast the finite-region analysis of Einstein's equations that underpins the ER=EPR program into the loop quantum gravity (LQG) framework. By translating curvature-energy uncertainty relations into holonomy-flux kinematics, and by…

General Relativity and Quantum Cosmology · Physics 2025-08-29 Fabrizio Tamburini

We argue that a conformally invariant extension of general relativity coupled to the Standard Model is the fundamental theory that needs to be quantized. We show that it can be treated by loop quantum gravity techniques. Through a gauge…

General Relativity and Quantum Cosmology · Physics 2017-01-24 Miguel Campiglia , Rodolfo Gambini , Jorge Pullin

We discuss various features and details of two versions of the Barrett-Crane spin foam model of quantum gravity, first of the Spin(4)-symmetric Riemannian model and second of the SL(2,C)-symmetric Lorentzian version in which all tetrahedra…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Hendryk Pfeiffer

We suggest a modification of the Barrett-Crane spin foam model of 4-dimensional Lorentzian general relativity motivated by the canonical quantization. The starting point is Lorentz covariant loop quantum gravity. Its kinematical Hilbert…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Sergei Alexandrov

We obtain the complete theory of Newton-Cartan gravity in a curved spacetime by considering the large $c$ limit of the vielbein formulation of General Relativity. Milne boosts originate from local Lorentzian transformations, and the special…

General Relativity and Quantum Cosmology · Physics 2018-11-13 Marco Cariglia

We construct a spin foam model of Yang-Mills theory coupled to gravity by using a discretized path integral of the BF theory with polynomial interactions and the Barret-Crane ansatz. In the Euclidian gravity case we obtain a vertex…

General Relativity and Quantum Cosmology · Physics 2009-01-16 A. Mikovic

We continue here the analysis of the previous paper of the Wheeler-DeWitt constraint operator for four-dimensional, Lorentzian, non-perturbative, canonical vacuum quantum gravity in the continuum. In this paper we derive the complete…

General Relativity and Quantum Cosmology · Physics 2009-10-28 T. Thiemann

The Hilbert space of a free massless particle moving on a group manifold is studied in details using canonical quantisation. While the simplest model is invariant under a global symmetry, $G \times G$, there is a very natural way to…

High Energy Physics - Theory · Physics 2015-06-26 Meifang Chu , Peter Goddard

A rigorous implementation of the Wheeler-Dewitt equations was derived in the context of Loop Quantum Gravity (LQG) and was coined Quantum Spin Dynamics (QSD). The Hamiltonian constraint of QSD was criticised as being too local and to…

General Relativity and Quantum Cosmology · Physics 2021-12-09 Thomas Thiemann , Madhavan Varadarajan

This work is mainly devoted to constructing a multisymplectic description of Lovelock's gravity, which is an extension of General Relativity. We establish a Griffiths variational problem for the Lovelock Lagrangian, obtaining the geometric…

Mathematical Physics · Physics 2020-10-05 Santiago Capriotti , Jordi Gaset , Narciso Román-Roy , Leandro Salomone

Barrett and Crane have proposed a model of simplicial Euclidean quantum gravity in which a central role is played by a class of Spin(4) spin networks called "relativistic spin networks" which satisfy a series of physically motivated…

General Relativity and Quantum Cosmology · Physics 2015-06-25 Michael P. Reisenberger

In this article we examine a Hamiltonian constraint operator governing the dynamics of simple quantum states, whose graph consists of a single six-valent vertex, in quantum-reduced loop gravity. To this end, we first derive the action of…

General Relativity and Quantum Cosmology · Physics 2025-05-01 Ilkka Mäkinen