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The central principle of affine quantum gravity is securing and maintaining the strict positivity of the matrix $\{\hg_{ab}(x)\}$ composed of the spatial components of the local metric operator. On spectral grounds, canonical commutation…

General Relativity and Quantum Cosmology · Physics 2009-11-07 John R. Klauder

Recently the neglected issue of the causal structure in the flat spacetime approach to Einstein's theory of gravity has been substantially resolved. Consistency requires that the flat metric's null cone be respected by the null cone of the…

General Relativity and Quantum Cosmology · Physics 2007-05-23 J. Brian Pitts , W. C. Schieve

The spatially flat Friedman-Robertson-Walker (FRW) cosmological model with a massless scalar field in loop quantum cosmology admits a description in terms of a completely solvable model. This has been used to prove that: i) the quantum…

General Relativity and Quantum Cosmology · Physics 2015-03-19 Alejandro Corichi , Edison Montoya

We study quantum cosmology with conformal matter comprising a perfect radiation fluid and a number of conformally coupled scalar fields. Focusing initially on the collective coordinates (minisuperspace) associated with homogeneous,…

High Energy Physics - Theory · Physics 2016-07-07 Steffen Gielen , Neil Turok

An affine quantization approach leads to a genuine quantum theory of general relativity by extracting insights from a short list of increasingly more complex, soluble, perturbably nonrenormalizable models.

General Relativity and Quantum Cosmology · Physics 2019-03-27 John R. Klauder

A gauge-invariant quantum theory of the Friedmann-Robertson-Walker (FRW) universe with dust is studied in terms of the Ashtekar variables. We use the reduced phase space quantization which has following advantages: (i) fundamental variables…

General Relativity and Quantum Cosmology · Physics 2010-11-11 Fumitoshi Amemiya , Tatsuhiko Koike

Improvement of the classical gravity with the running gravitational coupling obtained from asymptotically safe gravity, is a good way of considering the effects of quantum gravity. This is usually done for metric theories of gravity. Here…

General Relativity and Quantum Cosmology · Physics 2021-05-05 Raihaneh Moti , Ali Shojai

Affine quantization is a relatively new procedure, and it can solve many new problems. This essay reviews this new, and novel, procedure for particle problems, as well as those of fields and gravity. New quantization tools, which are…

General Physics · Physics 2023-10-19 John R. Klauder , Riccardo Fantoni

Perfect fluid Friedmann-Robertson-Walker quantum cosmological models for an arbitrary barotropic equation of state $p = \alpha\rho$ are constructed using Schutz's variational formalism. In this approach the notion of time can be recovered.…

General Relativity and Quantum Cosmology · Physics 2021-10-20 F. G. Alvarenga , J. C. Fabris , N. A. Lemos , G. A. Monerat

In the present work, we study the quantum cosmology description of closed Friedmann-Robertson-Walker models in the presence of a positive cosmological constant and a generic perfect fluid. We work in the Schutz's variational formalism. If…

General Relativity and Quantum Cosmology · Physics 2009-09-02 E. V. Corrêa Silva , G. A. Monerat , G. Oliveira-Neto , C. Neves , L. G. Ferreira Filho

The Quantum Wheeler-DeWitt operator can be derived from an affine commutation relation via the affine group representation formalism for gravity, wherein a family of gauge-diffeomorphism invariant affine coherent states are constructed from…

General Relativity and Quantum Cosmology · Physics 2014-09-29 Eyo Eyo Ita , Chou Ching-Yi

We present a gauge-invariant treatment of singularity resolution using loop quantum gravity techniques with respect to local SU(2) transformations. Our analysis reveals many novel features of quantum geometry which were till now hidden in…

General Relativity and Quantum Cosmology · Physics 2020-03-31 Klaus Liegener , Parampreet Singh

Canonical quantization has taught us great things. A common example is that of the harmonic oscillator, which is like swinging a ball on a string back and forth. However, the half-harmonic oscillator blocks the ball at the bottom and then…

Quantum Physics · Physics 2022-12-27 John R. Klauder

We derive an equation for the acceleration of a fluid element in the spherical gravitational collapse of a bounded compact object made up of an imperfect fluid. We show that non-singular as well as singular solutions arise in the collapse…

General Relativity and Quantum Cosmology · Physics 2014-11-17 Sukratu Barve , T. P. Singh , Louis Witten

In this paper we develope the main ideas of the quantized version of affinely-rigid (homogeneously deformable) motion. We base our consideration on the usual Schr\"odinger formulation of quantum mechanics in the configuration manifold which…

A brief summary of the application of coherent states in the examination of quantum dynamics of cosmological models is given. We discuss quantization maps, phase space probability distributions and semiclassical phase spaces. The…

General Relativity and Quantum Cosmology · Physics 2015-12-15 Przemyslaw Malkiewicz

In earlier Letters, we adopted a complex approach to quantum processes in the formation and evaporation of black holes. Taking Feynman's $+i\epsilon$ prescription, rather than than one of the more usual approaches, we calculated the quantum…

General Relativity and Quantum Cosmology · Physics 2009-11-11 A. N. St. J. Farley , P. D. D'Eath

We provide a full quantization of the vacuum Gowdy model with local rotational symmetry. We consider a redefinition of the constraints where the Hamiltonian Poisson-commutes with itself. We then apply the canonical quantization program of…

General Relativity and Quantum Cosmology · Physics 2017-12-06 Daniel Martín de Blas , Javier Olmedo , Tomasz Pawłowski

We examine the singularity resolution issue in quantum gravity by studying a new quantization of standard Friedmann-Robertson-Walker geometrodynamics. The quantization procedure is inspired by the loop quantum gravity programme, and is…

General Relativity and Quantum Cosmology · Physics 2009-11-10 V. Husain , O. Winkler

The big bang singularity of the expanding-universe Friedmann solution of the Einstein gravitational field equation can be regularized by the introduction of a degenerate metric and a nonzero length scale $b$. The result is a nonsingular…

General Relativity and Quantum Cosmology · Physics 2020-03-25 F. R. Klinkhamer