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Higher order curvature gravity has recently received a lot of attention due to the fact that it gives rise to cosmological models which seem capable of solving dark energy and quintessence issues without using "ad hoc" scalar fields. Such…

Astrophysics · Physics 2014-10-13 S. Capozziello , V. F. Cardone , S. Carloni , A. Troisi

The intuitive classical space-time picture breaks down in quantum gravity, which makes a comparison and the development of semiclassical techniques quite complicated. Using ingredients of the group averaging method to solve constraints one…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Martin Bojowald , Parampreet Singh , Aureliano Skirzewski

A set of diverse but mutually consistent results obtained in different settings has spawned a new view of loop quantum gravity and its physical implications, based on the interplay of operator calculations and effective theory: Quantum…

General Relativity and Quantum Cosmology · Physics 2012-12-27 Martin Bojowald

We derive the scalar-tensor Hamiltonian constraint to all orders of momenta when the canonical constraint algebra is deformed by a phase space function as predicted by some studies into loop quantum cosmology. We find that the momenta and…

General Relativity and Quantum Cosmology · Physics 2019-09-04 Rhiannon Cuttell , Mairi Sakellariadou

We present new second derivative, generally covariant theories of gravity for spherically symmetric spacetimes (general covariance is in the $t-r$ plane) belonging to the class where the spherically symmetric Einstein-Hilbert theory is…

General Relativity and Quantum Cosmology · Physics 2015-05-20 Rakesh Tibrewala

Holonomic quantum computation exploits a quantum state's non-trivial, matrix-valued geometric phase (holonomy) to perform fault-tolerant computation. Holonomies arising from systems where the Hamiltonian traces a continuous path through…

Quantum Physics · Physics 2022-02-08 Cornelis J. G. Mommers , Erik Sjöqvist

In loop quantum cosmology, one has to make a choice of SU(2) irreducible representation in which to compute holonomies and regularize the curvature of the connection. The systematic choice made in the literature is to work in the…

General Relativity and Quantum Cosmology · Physics 2017-04-26 Jibril Ben Achour , Suddhasattwa Brahma , Marc Geiller

Several quantum gravity approaches and field theory on an evolving lattice involve a discretization changing dynamics generated by evolution moves. Local evolution moves in variational discrete systems (1) are a generalization of the…

General Relativity and Quantum Cosmology · Physics 2014-10-28 Philipp A Hoehn

This article concerns the fate of local Lorentz invariance in quantum gravity, particularly for approaches in which a discrete structure replaces continuum spacetime. Some features of standard quantum mechanics, presented in a…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Joe Henson

Effects of space time geometry fluctuations on fermionic fields have recently been looked for in nuclear physics experiments, and were found to be much lower than predicted, at a phenomenological level, by loop quantum gravity. We show that…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Gustavo Dotti , Reinaldo J. Gleiser

Deviations from classical physics when distant quantum systems become correlated are interesting both fundamentally and operationally. There exist situations where the correlations enable collaborative tasks that are impossible within the…

Quantum Physics · Physics 2019-05-08 Farid Shahandeh , Austin P. Lund , Timothy C. Ralph

We study the physics of a single discrete gravitational extra dimension using the effective field theory for massive gravitons. We first consider a minimal discretization with 4D gravitons on the sites and nearest neighbor hopping terms. At…

High Energy Physics - Theory · Physics 2011-07-19 Nima Arkani-Hamed , Matthew D. Schwartz

We give from first principles the non-relativistic limit of scalar and Dirac fields in curved spacetime. We aim to find general relativistic corrections to the quantum theory of particles affected by Newtonian gravity, a regime nowadays…

High Energy Physics - Theory · Physics 2023-06-06 Riccardo Falcone , Claudio Conti

In this paper we extract from a large-$r$ expansion of the vacuum Einstein's equations a dynamical system governing the time evolution of an infinity of higher-spin charges. Upon integration, we evaluate the canonical action of these…

High Energy Physics - Theory · Physics 2022-05-02 Laurent Freidel , Daniele Pranzetti , Ana-Maria Raclariu

In this thesis, we study the implications of Quantum Gravity models for the dynamics of spacetime and the ensuing departures from classical General Relativity. The main focus is on cosmological applications, particularly the impact of…

General Relativity and Quantum Cosmology · Physics 2018-04-09 Marco de Cesare

Recently, some problems have been found in the definition of the partial derivative in the case of the presence of both explicit and implicit functional dependencies in the classical analysis. In this talk we investigate the influence of…

Mathematical Physics · Physics 2007-05-23 Valeri V. Dvoeglazov

Canonical gravity in real Ashtekar-Barbero variables is generalized to allow for fermionic matter. The resulting torsion changes several expressions in Holst's original vacuum analysis, which are summarized here. This in turn requires…

General Relativity and Quantum Cosmology · Physics 2008-11-07 Martin Bojowald , Rupam Das

It is shown that the difficulties in formulating the quantum field theory on discrete spacetime appear already in classical dynamics of one degree of freedom on discrete time. The difference equation of motion which maintains a conserved…

High Energy Physics - Theory · Physics 2007-05-23 Hiroshi Yamamoto , Akihisa Hayashi , Takaaki Hashimoto , Minoru Horibe

Canonical methods of quasiclassical dynamics make it possible to go beyond a strict background approximation for cosmological perturbations by including independent fields such as correlation degrees of freedom. New models are introduced…

General Relativity and Quantum Cosmology · Physics 2021-07-06 Martin Bojowald , Ding Ding

We study quantum stability bound on the mass of scalaron in generic theories of $f(R)$ gravity. We show that in these scenarios, the scalaron mass increases faster with local density of the environment than one loop quantum correction to it…

High Energy Physics - Theory · Physics 2016-05-04 R. Gannouji , M. Sami , I. Thongkool