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Related papers: Curving Flat Space-Time by Deformation Quantizatio…

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We use Dirac's method for the quantization of constrained systems in order to quantize a spatially flat Friedmann-Lema\^{i}tre-Robertson-Walker spacetime in the context of $f(Q)$ cosmology. When the coincident gauge is considered, the…

General Relativity and Quantum Cosmology · Physics 2021-10-22 N. Dimakis , A. Paliathanasis , T. Christodoulakis

Any quantum system interacting with a complex environment undergoes decoherence. Empty space is filled with vacuum energy due to matter fields in their ground state and represents an underlying environment that any quantum particle has to…

General Relativity and Quantum Cosmology · Physics 2009-08-26 Paolo M. Bonifacio

We demonstrate how one can distinguish a curved 4-dimensional spacetime from a flat one, when it is possible, relying only on the causality relations between events. It is known that it is possible only for spacetimes that are not…

General Relativity and Quantum Cosmology · Physics 2023-02-24 A. V. Nenashev , S. D. Baranovskii

We consider the nonrelativistic particle moving on noncommutative space-time in the presence of constant force $\vec{F}$. Further, following the paper M. Daszkiewicz, C.J. Walczyk, Phys. Rev. D 77, 105008 (2008); arXiv: 0802.3575 [math-ph],…

Mathematical Physics · Physics 2010-07-28 Marcin Daszkiewicz

We have previously presented a version of the Weak Equivalence Principle for a quantum particle as an exact analog of the classical case, based on the Heisenberg picture analysis of free particle motion. Here, we take that to a full…

General Relativity and Quantum Cosmology · Physics 2025-06-17 Otto C. W. Kong

This work studies the quantum cosmology of a closed, spatially homogeneous, and isotropic FLRW minisuperspace model with electromagnetic radiation as a matter content. We solve the associated Wheeler-DeWitt (WDW) equation using the…

General Relativity and Quantum Cosmology · Physics 2023-04-20 S. Jalalzadeh , A. Mohammadi , D. Demir

This paper is devoted to investigation of the quantum Friedman-Robertson-Walker universe with matter satisfying the equation of state $p=w\rho$, where $w$ is an almost arbitrary constant. The procedure starts with a reduced Lagrangian,…

General Relativity and Quantum Cosmology · Physics 2010-09-23 Przemyslaw Malkiewicz

Deformation quantization is a formal deformation of the algebra of smooth functions on some manifold. In the classical setting, the Poisson bracket serves as an initial conditions, while the associativity allows to proceed to higher orders.…

High Energy Physics - Theory · Physics 2015-09-22 V. G. Kupriyanov , D. V. Vassilevich

Based on the conventional metric tensor and driven by a nearly constant energy density, cosmic inflation, characterized by a remarkably accelerated expansion, was proposed as an early epoch in the Universe. The energy density is typically…

General Relativity and Quantum Cosmology · Physics 2026-05-05 Swapnil K. Singh , Saleh O. Allehabi , Azzah A. Alshehri , Mahmoud Nasar , Abdel Nasser Tawfik

We present and expand the simplest possible quantum cosmological bouncing model already discussed in previous works: the trajectory formulation of quantum mechanics applied to cosmology (through the Wheeler-De Witt equation) in the FLRW…

General Relativity and Quantum Cosmology · Physics 2016-07-20 Patrick Peter , Sandro D. P. Vitenti

Several recent studies have concerned the faith of classical symmetries in quantum space-time. In particular, it appears likely that quantum (discretized, noncommutative,...) versions of Minkowski space-time would not enjoy the classical…

General Relativity and Quantum Cosmology · Physics 2017-08-23 Giovanni Amelino-Camelia

Doubly special relativity has been studied for the last twenty years as a way to go beyond the special relativistic kinematics, trying to capture residual effects of a quantum gravity theory. In particular, in doubly special relativity the…

General Relativity and Quantum Cosmology · Physics 2022-07-19 J. J. Relancio

The possible role of gravity in a noncommutative geometry is investigated. Due to the Moyal *-product of fields in noncommutative geometry, it is necessary to complexify the metric tensor of gravity. We first consider the possibility of a…

High Energy Physics - Theory · Physics 2009-10-31 J. W. Moffat

We consider the symmetric teleparallel $f\left( Q\right) $-gravity in Friedmann--Lema\^{\i}tre--Robertson--Walker cosmology with nonzero spatial curvature. For a nonlinear $f\left( Q\right) $ model there exist always the limit of General\…

General Relativity and Quantum Cosmology · Physics 2023-10-09 Andronikos Paliathanasis

We solve the source free electromagnetic wave equation in Friedmann-Robertson-Walker space-times for curvature $K=0$ and $K=-1$. Deriving a solution expression in the form of spherical means we deduce and compare two properties of the…

Analysis of PDEs · Mathematics 2019-12-20 Walter Craig , Mikale Reddy

We describe a quantum limit to measurement of classical spacetimes. Specifically, we formulate a quantum Cramer-Rao lower bound for estimating the single parameter in any one-parameter family of spacetime metrics. We employ the locally…

Quantum Physics · Physics 2017-11-15 T. G. Downes , J. R. van Meter , E. Knill , G. J. Milburn , C. M. Caves

The curvature of a spacetime, either in a topological sense, or averaged over super-horizon-sized patches, is often equated with the global curvature term that appears in Friedmann's equation. In general, however, the Universe is…

Cosmology and Nongalactic Astrophysics · Physics 2021-04-21 Chi Tian , Stefano Anselmi , Matthew F. Carney , John T. Giblin , James Mertens , Glenn Starkman

In this work we present a derivation of Dirac's equation in a curved space-time starting from a Weyl-invariant action principle in 4+K dimensions. The Weyl invariance of Dirac's equation (and of Quantum Mechanics in general) is made…

Quantum Physics · Physics 2021-03-10 Enrico Santamato , Francesco De Martini

We establish a deformation framework for highly symmetric solutions to the Einstein equations. In this framework, four-dimensional metrics are constructed from three-dimensional {\eta}-Einstein metrics admitting a deformation determined by…

General Relativity and Quantum Cosmology · Physics 2026-04-23 Hiroshi Kozaki , Satsuki Matsuno , Tatsuhiko Koike , Yoshiyuki Morisawa , Hideki Ishihara

We apply a recent proposal for defining states and observables in quantum gravity to simple models. First, we consider a Klein-Gordon particle in an ex- ternal potential in Minkowski space and compare our proposal to the theory ob- tained…

General Relativity and Quantum Cosmology · Physics 2009-10-22 A. Higuchi , R. M. Wald