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Ambiguities of the so-called Thiemann regularization in Loop Quantum Cosmology lead to freedom in how to construct a particular quantization prescription. So far three distinct examples of such have been proposed in the literature. For two…

General Relativity and Quantum Cosmology · Physics 2021-12-16 Maciej Kowalczyk

In loop quantum cosmology, a difference equation for the wave function describes the evolution of a universe model. This is different from the differential equations that arise in Wheeler-DeWitt quantizations, and some aspects of general…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Martin Bojowald , Adam Rej

The improved dynamics of loop quantum cosmology is extended to include the Bianchi type II model. Because these space-times admit both anisotropies and non-zero spatial curvature, certain technical difficulties arise over and above those…

General Relativity and Quantum Cosmology · Physics 2010-01-07 Abhay Ashtekar , Edward Wilson-Ewing

The key ingredient for lattice regularized quantum gravity is diffeomorphism symmetry. We formulate a lattice functional integral for quantum gravity in terms of fermions. This allows for a diffeomorphism invariant functional measure and…

General Relativity and Quantum Cosmology · Physics 2015-06-03 C. Wetterich

We review recent work in the lattice approach to random surfaces and quantum gravity. Our task is made somewhat easier by some very interesting results, particularly in four dimensions, that have appeared recently and which are reported…

High Energy Physics - Lattice · Physics 2009-10-28 D. A. Johnston

Loop quantum cosmology leads to a difference equation for the wave function of a universe, which in general has solutions changing rapidly even when the volume changes only slightly. For a semiclassical regime such small-scale oscillations…

General Relativity and Quantum Cosmology · Physics 2009-03-24 Daniel Cartin , Gaurav Khanna , Martin Bojowald

The study of nonlinear phenomena in systems with many degrees of freedom often relies on complex numerical simulations. In trying to model realistic situations, these systems may be coupled to an external environment which drives their…

High Energy Physics - Lattice · Physics 2009-10-28 Julian Borrill , Marcelo Gleiser

Inhomogeneous quantum cosmology is modeled as a dynamical system of discrete patches, whose interacting many-body equations can be mapped to a non-linear minisuperspace equation by methods analogous to Bose-Einstein condensation.…

General Relativity and Quantum Cosmology · Physics 2012-12-18 Martin Bojowald , Alexander L. Chinchilli , Christine C. Dantas , Matthew Jaffe , David Simpson

We investigate the cosmological behavior in a universe governed by time asymmetric extensions of general relativity, which is a novel modified gravity based on the addition of new, time-asymmetric, terms on the Hamiltonian framework, in a…

General Relativity and Quantum Cosmology · Physics 2015-11-11 Genly Leon , Emmanuel N. Saridakis

Modified gravity theories have received increased attention lately to understand the late time acceleration of the universe. This viewpoint essentially modifies the geometric components of the universe. Among numerous extension to…

General Relativity and Quantum Cosmology · Physics 2019-05-23 Parth Shah , Gauranga C. Samanta

The determination of real-time dynamics of strongly coupled quantum fields is a central goal of modern nuclear and particle physics, which requires insight into quantum field theory beyond the weak-coupling approximation. While lattice QCD…

High Energy Physics - Lattice · Physics 2023-01-11 Alexander Rothkopf

New and non-trivial properties of off-shell instantons in loop quantum cosmology show that dynamical signature change naturally cures recently observed problems in the semiclassical path integral of quantum gravity. If left unsolved, these…

General Relativity and Quantum Cosmology · Physics 2018-11-20 Martin Bojowald , Suddhasattwa Brahma

Harmonic oscillator in noncommutative two dimensional lattice are investigated. Using the properties of non-differential calculus and its applications to quantum mechanics, we provide the eigenvalues and eigenfunctions of the corresponding…

High Energy Physics - Theory · Physics 2019-04-11 Dine Ousmane Samary , Sêcloka Lazare Guedezounme , Antonin Danvidé Kanfon

A careful study of the classical/quantum connection with the aid of coherent states offers new insights into various technical problems. This analysis includes both canonical as well as closely related affine quantization procedures. The…

High Energy Physics - Theory · Physics 2015-06-12 John R. Klauder

Holonomy corrections to scalar perturbations are investigated in the loop quantum cosmology framework. Due to the effective approach, modifications of the algebra of constraints generically lead to anomalies. In order to remove those…

General Relativity and Quantum Cosmology · Physics 2012-11-01 Thomas Cailleteau , Jakub Mielczarek , Aurelien Barrau , Julien Grain

We review aspects of loop quantum gravity in a pedagogical manner, with the aim of enabling a precise but critical assessment of its achievements so far. We emphasise that the off-shell (`strong') closure of the constraint algebra is a…

High Energy Physics - Theory · Physics 2009-11-11 Hermann Nicolai , Kasper Peeters , Marija Zamaklar

We present a systematic study of the cosmological dynamics resulting from an effective Hamiltonian, recently derived in loop quantum gravity using Thiemann's regularization and earlier obtained in loop quantum cosmology (LQC) by keeping the…

General Relativity and Quantum Cosmology · Physics 2018-04-25 Bao-Fei Li , Parampreet Singh , Anzhong Wang

Within a perturbative cosmological regime of loop quantum gravity corrections to effective constraints are computed. This takes into account all inhomogeneous degrees of freedom relevant for scalar metric modes around flat space and results…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Martin Bojowald , Hector Hernandez , Mikhail Kagan , Aureliano Skirzewski

Anisotropic cosmological models are constructed in $f(R,T)$ gravity theory to investigate the dynamics of universe concerning the late time cosmic acceleration. Using a more general and simple approach, the effect of the coupling constant…

General Physics · Physics 2018-10-05 B. Mishra , Sankarsan Tarai , S. K. Tripathy

During their operation, due to shifts in environmental conditions, devices undergo various forms of detuning from their optimal settings. Typically, this is addressed through control loops, which monitor variables and the device…

Quantum Physics · Physics 2024-04-17 T. Crosta , L. Rebón , F. Vilariño , J. M. Matera , M. Bilkis