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Recently, uniqueness theorems were constructed for the representation used in Loop Quantum Gravity. We explore the existence of alternate representations by weakening the assumptions of the so called LOST uniqueness theorem. The weakened…

General Relativity and Quantum Cosmology · Physics 2015-01-30 Madhavan Varadarajan

We evaluated the scattering amplitude of neutral scalar particles at one-loop order in the context of effective field theory of quantum gravity in the presence of a cosmological constant. Our study suggests that quantum gravitational…

High Energy Physics - Theory · Physics 2013-12-02 A. C. Lehum

Phase spaces with nontrivial geometry appear in different approaches to quantum gravity and can also play a role in e.g. condensed matter physics. However, so far such phase spaces have only been considered for particles or strings. We…

High Energy Physics - Theory · Physics 2017-05-30 Tomasz Trześniewski

This article lays out a complete framework for an effective theory of cosmological perturbations with corrections from canonical quantum gravity. Since several examples exist for quantum-gravity effects that change the structure of…

General Relativity and Quantum Cosmology · Physics 2015-05-27 Aurelien Barrau , Martin Bojowald , Gianluca Calcagni , Julien Grain , Mikhail Kagan

When quantum fields are studied on manifolds with boundary, the corresponding one-loop quantum theory for bosonic gauge fields with linear covariant gauges needs the assignment of suitable boundary conditions for elliptic differential…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Giampiero Esposito

We apply a hybrid approach which combines loop and Fock quantizations to fully quantize the linearly polarized Gowdy $T^3$ model in the presence of a massless scalar field with the same symmetries as the metric. Like in the absence of…

General Relativity and Quantum Cosmology · Physics 2011-05-12 Mercedes Martín-Benito , Daniel Martín-de Blas , Guillermo A. Mena Marugán

Loop Quantum Gravity (L.Q.G.) is one of the two most promising tentative theory for a quantum description of gravity. When applied to the entire universe, the so-called Loop Quantum Cosmology (L.Q.C.) framework offers microscopical models…

General Relativity and Quantum Cosmology · Physics 2014-11-20 J. Grain

Based on empirical evidence, quantum systems appear to be strictly linear and gauge invariant. This work uses concise mathematics to show that quantum eigenvalue equations on a one dimensional ring can either be gauge invariant or have a…

Quantum Physics · Physics 2014-07-15 Arthur Davidson

Gauge invariant regularization of quantum field theory in the framework of Light-Front (LF) Hamiltonian formalism via introducing a lattice in transverse coordinates and imposing boundary conditions in LF coordinate $x^-$ for gauge fields…

High Energy Physics - Theory · Physics 2009-11-10 S. A. Paston , E. V. Prokhvatilov , V. A. Franke

We consider the one-loop corrected geometry and thermodynamics of a rotating BTZ black hole by way of a dimensionally reduced dilaton model. The analysis begins with a comprehensive study of the non-extremal solution after which two…

High Energy Physics - Theory · Physics 2009-10-31 A. J. M. Medved , G. Kunstatter

There exist several different proposals for a measure in Quantum Gravity theories. Although sometimes being labelled as non covariant, the measure derived in [7] for GR has the particularity that, in the extremal, the volume divergences…

General Relativity and Quantum Cosmology · Physics 2026-03-05 O. P. Santillán

We discuss how a cyclic model for the flat universe can be constructively derived from Loop Quantum Gravity. This model has a lower bounce, at small values of the scale factor, which shares many similarities with that of Loop Quantum…

General Relativity and Quantum Cosmology · Physics 2017-06-13 Francesco Cianfrani , Jerzy Kowalski-Glikman , Giacomo Rosati

The degree of freedom of the scalar field in scalar-tensor gravity is employed as "time" to deparametrize the Hamiltonian constraint of the theory. The deparametrized system is then nonperturbatively quantized by the approach of loop…

General Relativity and Quantum Cosmology · Physics 2026-03-02 Faqiang Yuan , Haida Li , Shengzhi Li , Yongge Ma

The use of techniques from loop quantum gravity for cosmological models may solve some difficult problems in quantum cosmology. The solutions under a number of circumstances have been well studied. We will analyse the behaviour of solutions…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Daniel Green , William G. Unruh

Nonlinear generalizations of teleparallel gravity entail the modification of a Lagrangian that is pseudoinvariant under local Lorentz transformations of the tetrad field. This procedure consequently leads to the loss of the local…

General Relativity and Quantum Cosmology · Physics 2020-04-27 Rafael Ferraro , María José Guzmán

In this paper we calculate $\mathcal{O}(\mu^4)$ corrections from holonomies in the Loop Quantum Gravity, usually not taken into account. Allowance of the corrections of this kind is equivalent with the choice of the new quatization scheme.…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Jakub Mielczarek , Marek Szydlowski

Quantum phase transitions in certain non-Hermitian systems controlled by non-tridiagonal Hamiltonian matrices are found anomalous. In contrast to the known models with tridiagonal-matrix structure in which the geometric multiplicity of the…

Quantum Physics · Physics 2020-06-08 Miloslav Znojil , Denis I. Borisov

Quantum reduced loop gravity is designed to consistently study symmetry reduced systems within the loop quantum gravity framework. In particular, it bridges the gap between the effective cosmological models of loop quantum cosmology and the…

General Relativity and Quantum Cosmology · Physics 2018-12-05 Emanuele Alesci , Aurélien Barrau , Gioele Botta , Killian Martineau , Gabriele Stagno

This thesis is dedicated to the study of symmetries in reduced models of gravity, with some frozen degrees of freedom. We focus on the minisuperspace reduction whith a finite number of degrees of freedom. Minisuperspaces are treated as…

General Relativity and Quantum Cosmology · Physics 2022-11-10 Francesco Sartini

An effective Lagrangian approach, partly inspired by Quantum Loop Cosmology (QLC), is presented and formulated in a non flat FLRW space-times, making use of modified gravitational models. The models considered are non generic, and their…

General Relativity and Quantum Cosmology · Physics 2020-05-15 Alessandro Casalino , Lorenzo Sebastiani , Luciano Vanzo , Sergio Zerbini