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Related papers: Symmetry Reduced Loop Quantum Gravity: A Bird's Ey…

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In this essay, we argue that certain aspects of the measurement require revision in Quantum Gravity. Using entropic arguments, we propose that the number of measurement outcomes and the accuracy (or the range) of the measurement are limited…

High Energy Physics - Theory · Physics 2024-08-28 Juanca Carrasco-Martinez

We systematically study the top-down model of loop quantum black holes (LQBHs), recently derived by Alesci, Bahrami and Pranzetti (ABP). To understand the structure of the model, we first derive several well-known LQBH solutions by taking…

General Relativity and Quantum Cosmology · Physics 2022-12-26 Wen-Cong Gan , Geeth Ongole , Emanuele Alesci , Yang An , Fu-Wen Shu , Anzhong Wang

Within a generally covariant Hamiltonian framework of loop quantum gravity (LQG), two black hole models parameterized by a quantum correction $\zeta$ have recently been constructed. Using extreme mass-ratio inspirals (EMRIs) as…

General Relativity and Quantum Cosmology · Physics 2026-02-10 Ruo-Ting Chen , Guoyang Fu , Dan Zhang , Jian-Pin Wu

A mathematically consistent rotating black hole model in loop quantum gravity (LQG) is yet lacking. The scarcity of rotating black hole solutions in LQG substantially hampers the development of testing LQG from observations, e.g., from the…

General Relativity and Quantum Cosmology · Physics 2023-01-25 Shafqat Ul Islam , Jitendra Kumar , Rahul Kumar Walia , Sushant G. Ghosh

I review the lattice approach to quantum gravity, and how it relates to the non-trivial ultraviolet fixed point scenario of the continuum theory. After a brief introduction covering the general problem of ultraviolet divergences in gravity…

General Relativity and Quantum Cosmology · Physics 2009-04-17 Herbert W. Hamber

Weak gravitational lensing surveys measure the distortion of the image of distant sources due to the deflections of light rays by the fluctuations of the gravitational potential along the line of sight. Since they probe the non-linear…

Astrophysics · Physics 2009-11-13 Dipak Munshi , Patrick Valageas

By reducing variance induced by gravitational lensing, likelihood-based de-lensing techniques have true potential to extract significantly more information from deep and high-resolution Cosmic Microwave Background (CMB) data than…

Cosmology and Nongalactic Astrophysics · Physics 2025-03-13 Julien Carron

The "improved dynamics" of loop quantum cosmology is extended to include anisotropies of the Bianchi I model. As in the isotropic case, a massless scalar field serves as a relational time parameter. However, the extension is non-trivial…

General Relativity and Quantum Cosmology · Physics 2010-04-14 Abhay Ashtekar , Edward Wilson-Ewing

Gravitational lenses can provide crucial information on the geometry of the Universe, on the cosmological scenario of formation of its structures as well as on the history of its components with look-back time. In this review, I focus on…

Astrophysics · Physics 2009-10-31 Y. Mellier

A phenomenology for the deep spatial geometry of loop quantum gravity is introduced. In the context of a simple model, an atom of space, it is shown how purely combinatorial structures can affect observations. The angle operator is used to…

General Relativity and Quantum Cosmology · Physics 2014-11-21 Seth A. Major

Weak gravitational lensing has several important effects on the cosmic microwave background (CMB): it changes the CMB power spectra, induces non-Gaussianities, and generates a B-mode polarization signal that is an important source of…

Astrophysics · Physics 2007-05-23 Antony Lewis , Anthony Challinor

The information theory approach is suggested to the Cosmic Microwave Background (CMB) problem for negatively curved homogeneous and isotropic Universe. Namely, the Kolmogorov complexity of anisotropy of spots in CMB sky maps is proposed as…

Astrophysics · Physics 2009-10-31 V. G. Gurzadyan

Using a form of modified dispersion relations derived in the context of quantum geometry, we investigate limits set by current observations on potential corrections to Lorentz invariance. We use a phenomological model in which there are…

High Energy Physics - Phenomenology · Physics 2008-11-26 Tomasz J. Konopka , Seth A. Major

In this note we investigate the impact of some "new-physics", beyond the electro-weak Standard Model of elementary particles, on the Higgs vacuum. We consider both un-particle and quantum gravity induced effects. We find that even if the…

High Energy Physics - Theory · Physics 2012-11-29 Patricio Gaete , Euro Spallucci

A midi-superspace model is a field theory obtained by symmetry reduction of a parent gravitational theory. Such models have proven useful for exploring the classical and quantum dynamics of the gravitational field. I present 3 recent…

General Relativity and Quantum Cosmology · Physics 2011-04-15 C. G. Torre

We calculate deviations in cosmological observables as a function of parameters in a class of connection-based models of quantum gravity. In this theory non-trivial modifications to the background cosmology can occur due to a distortion of…

Cosmology and Nongalactic Astrophysics · Physics 2023-02-01 Michael W. Toomey , Savvas Koushiappas , Bruno Alexandre , João Magueijo

Investigating the accelerated expansion of the universe with cosmography is a best method to constraint cosmological models. In this work, in the $F(G)$ modified gravity framework, we obtain equations of motion in a flat FRW metric. Then we…

General Physics · Physics 2012-06-04 M. R. Setare , N. Mohammadipour

Recently, the cosmological tensions, $H_0$ and $S_8$ in particular, have inspired modification of both pre- and postrecombination physics simultaneously. Early dark energy is a promising pre-recombination solution of the $H_0$ tension,…

Cosmology and Nongalactic Astrophysics · Physics 2023-09-14 Gen Ye , Jun-Qian Jiang , Yun-Song Piao

The lensing convergence field describing the weak lensing effect of the Cosmic Microwave Background (CMB) radiation is expected to be subject to mild deviations from Gaussianity. We perform a suite of full-sky lensing simulations using ray…

Cosmology and Nongalactic Astrophysics · Physics 2025-03-18 Jan Hamann , Yuqi Kang

We reconsider the Rovelli-Smolin model of gravity coupled to the Klein-Gordon time field with an eye towards capturing the degrees of freedom of the scalar field lost in the framework in which time is deparametrized by the scalar field.…

General Relativity and Quantum Cosmology · Physics 2016-02-03 Jerzy Lewandowski , Hanno Sahlmann
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