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The restriction to invariant connections in a Friedmann-Robertson-Walker space-time is discussed via the analysis of the Dirac brackets associated with the corresponding gauge fixing. This analysis allows us to establish the proper…

General Relativity and Quantum Cosmology · Physics 2015-05-27 Francesco Cianfrani , Giovanni Montani

We give a non-technical description of the differences of quantisation of the bosonic string between the usual Fock-space approach and the treatment inspired by methods of loop quantum gravity termed the LCQ string. We point out the role of…

High Energy Physics - Theory · Physics 2007-05-23 Robert C. Helling

We extend ideas developed for the loop representation of quantum gravity to diffeomorphism-invariant gauge theories coupled to fermions. Let P -> Sigma be a principal G-bundle over space and let F be a vector bundle associated to P whose…

High Energy Physics - Theory · Physics 2015-06-26 John C. Baez , Kirill V. Krasnov

We present and analyze a gauge-invariant quantum theory of the Friedmann-Robertson-Walker universe with dust. We construct the reduced phase space spanned by gauge-invariant quantities by using the so-called relational formalism at the…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Fumitoshi Amemiya , Tatsuhiko Koike

We propose a manifestly covariant canonical method of field quantization based on the classical De Donder-Weyl covariant canonical formulation of field theory. Owing to covariance, the space and time arguments of fields are treated on an…

High Energy Physics - Theory · Physics 2009-01-07 H. Nikolic

A suitable deformation of the Hopf algebra of the creation and annihilation operators for a complex scalar field, initially quantized in Minkowski space--time, induces the canonical quantization of the same field in a generic gravitational…

Quantum Physics · Physics 2007-05-23 A. Iorio , G. Lambiase , G. Vitiello

We analyze the phase space of gravity non-minimally coupled to a scalar field in a generic local Lorentz frame. We reduce the set of constraints to a first-class one by fixing a specific hypersurfaces in the phase space. The main issue of…

General Relativity and Quantum Cosmology · Physics 2013-05-29 F. Cianfrani , G. Montani

We achieve a group theoretical quantization of the flat Friedmann-Robertson-Walker model coupled to a massless scalar field adopting the improved dynamics of loop quantum cosmology. Deparemeterizing the system using the scalar field as…

General Relativity and Quantum Cosmology · Physics 2013-05-30 Etera R. Livine , Mercedes Martín-Benito

Recently, a generally covariant reformulation of 2 dimensional flat spacetime free scalar field theory known as Parameterised Field Theory was quantized using Loop Quantum Gravity (LQG) type `polymer' representations. Physical states were…

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

By regarding the vacuum as a perfect fluid with equation of state p=-rho, de Sitter's cosmological model is quantized. Our treatment differs from previous ones in that it endows the vacuum with dynamical degrees of freedom. Instead of being…

General Relativity and Quantum Cosmology · Physics 2015-06-25 Flavio G. Alvarenga , Nivaldo A. Lemos

The discrete spatial geometry underlying Loop Quantum Gravity (LQG) is degenerate almost everywhere. This is at apparent odds with the non- degeneracy of asymptotically flat metrics near spatial infinity. Koslowski generalised the LQG…

General Relativity and Quantum Cosmology · Physics 2015-06-18 Miguel Campiglia , Madhavan Varadarajan

We apply a type of background independent "polymer" quantization to a free scalar field in a flat spacetime. Using semi-classical states, we find an effective wave equation that is both nonlinear and Lorentz invariance violating. We solve…

High Energy Physics - Theory · Physics 2009-09-30 Golam Mortuza Hossain , Viqar Husain , Sanjeev S. Seahra

We study a model for quantum gravity on a circle in which the notion of a classical metric tensor is replaced by a quantum metric with an inhomogeneous transformation law under diffeomorphisms. This transformation law corresponds to the…

General Relativity and Quantum Cosmology · Physics 2010-04-06 R. J. Henderson , S. G. Rajeev

We discuss the issue of unitarity in particular quantum cosmological models with scalar field. The time variable is recovered, in this context, by using the Schutz's formalism for a radiative fluid. Two cases are considered: a phantom…

General Relativity and Quantum Cosmology · Physics 2015-09-23 C. R. Almeida , A. B. Batista , J. C. Fabris , P. R. L. V. Moniz

The ordinary Landau problem consists of describing a charged particle in time-independent magnetic field. In the present case the problem is generalized onto time-dependent uniform electric fields with time-dependent mass and harmonic…

Quantum Physics · Physics 2021-11-10 Latévi Mohamed Lawson

Canonical quantization covers a broad class of classical systems, but that does not include all the problems of interest. Affine quantization has the benefit of providing a successful quantization of many important problems including the…

General Physics · Physics 2021-05-10 John R. Klauder

A model for quantum gravity in one (time) dimension is discussed, based on Regge's discrete formulation of gravity. The nature of exact continuous lattice diffeomorphisms and the implications for a regularized gravitational measure are…

High Energy Physics - Theory · Physics 2009-10-28 Herbert W. Hamber , Ruth M. Williams

We give a simple and self-contained construction of of the $P(\Phi)$ Euclidean Quantum Field Theory in the plane and verify the Osterwalder-Schrader axioms: translational and rotational invariance, reflection positivity and regularity. In…

Mathematical Physics · Physics 2024-06-05 Paweł Duch , Wojciech Dybalski , Azam Jahandideh

We derive the invariant measure on the manifold of multimode quantum Gaussian states, induced by the Haar measure on the group of Gaussian unitary transformations. To this end, by introducing a bipartition of the system in two disjoint…

Quantum Physics · Physics 2013-01-07 C. Lupo , S. Mancini , A. De Pasquale , P. Facchi , G. Florio , S. Pascazio

If the diffeomorphism symmetry of general relativity is fully implemented into a path integral quantum theory, the path integral leads to a partition function which is an invariant of smooth manifolds. We comment on the physical…

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