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In various background independent approaches, quantum gravity is defined in terms of a field propagation kernel: a sum over paths interpreted as a transition amplitude between 3-geometries, expected to project quantum states of the geometry…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Federico Mattei , Carlo Rovelli , Simone Speziale , Massimo Testa

The Wheeler-DeWitt equation for the Bianchi Class A cosmological models is expressed generally in terms of the second-order differential equation like the Klein-Gordon equation. To obtain the positive-definite probability density, a new…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Hidetomo Yamazaki

In this article we perform the Wheeler-DeWitt quantization for Bianchi type $I$ anisotropic cosmological model in the presence of a scalar field minimally coupled to the Einstein-Hilbert gravity theory. We also consider the cosmological…

General Relativity and Quantum Cosmology · Physics 2019-08-14 Saumya Ghosh , Sunandan Gangopadhyay , Prasanta K. Panigrahi

In this paper, we invoke a generalized uncertainty principle (GUP) in the symmetry-reduced cosmological Hamiltonian for a universe driven by a quintessence scalar field with potential. Our study focuses on semi-classical regime. In…

General Relativity and Quantum Cosmology · Physics 2024-05-15 Gaurav Bhandari , S. D. Pathak , Manabendra Sharma , Anzhong Wang

The transition probability in first-order perturbation theory for an Unruh-DeWitt detector coupled to a massless scalar field in Minkowski space is calculated. It has been shown recently that the conventional $i\epsilon$ regularisation…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Alejandro Satz

Polymer models are effective in describing quantum gravity effects around the initial singularity, leading to its replacement by bouncing surfaces on which the curvature and densities are finite. Their properties depend on the space-time…

General Relativity and Quantum Cosmology · Physics 2026-02-23 D. A. Cook , A. Olimpieri , I. P. R. Baranov , H. A. Borges , S. Carneiro

We analyze some relevant semiclassical and quantum features of the implementation of Polymer Quantum Mechanics to the phenomenology of the flat isotropic Universe. We firstly investigate a parallelism between the semiclassical polymer…

General Relativity and Quantum Cosmology · Physics 2020-04-17 Gabriele Barca , Paolo Di Antonio , Giovanni Montani , Alberto Patti

We present a candidate quantum field theory of gravity with dynamical critical exponent equal to z=3 in the UV. (As in condensed matter systems, z measures the degree of anisotropy between space and time.) This theory, which at short…

High Energy Physics - Theory · Physics 2009-04-22 Petr Horava

Various approaches to Quantum Gravity (such as String Theory and Doubly Special Relativity), as well as black hole physics predict a minimum measurable length, or a maximum observable momentum, and related modifications of the Heisenberg…

High Energy Physics - Theory · Physics 2009-07-29 Ahmed Farag Ali , Saurya Das , Elias C. Vagenas

The quantization of the most general Bianchi Type II geometry -with all six scale factors, as well as the lapse function and the shift vector, present- is considered. In an earlier work, a first reduction of the initial 6-dimensional…

General Relativity and Quantum Cosmology · Physics 2009-10-09 T. Christodoulakis , G. O. Papadopoulos

In this work we explore the dynamics of the generalized hybrid metric-Palatini theory of gravity in the weak-field, slow-motion regime. We start by introducing the equivalent scalar-tensor representation of the theory, which contains two…

General Relativity and Quantum Cosmology · Physics 2021-12-14 João Luís Rosa , Francisco S. N. Lobo , Gonzalo J. Olmo

We revisit the famous Coleman-de Luccia formalism for decay of false vacuum in gravitational theory. Since the corresponding wave function is time-independent we argue that its instanton's interpretation as the decay rate probability is…

General Relativity and Quantum Cosmology · Physics 2019-07-30 J. Kristiano , R. D. Lambaga , H. S. Ramadhan

We consider the induced $2$d-gravity in the minisuperspace approach. The general solution to the Wheeler-DeWitt equation is given in terms of different kind of Bessel functions of purely real or imaginary orders. We study the properties of…

General Relativity and Quantum Cosmology · Physics 2011-04-20 J. Navarro-Salas , M. Navarro , V. Aldaya

Wilk's theorem, which offers universal chi-squared approximations for likelihood ratio tests, is widely used in many scientific hypothesis testing problems. For modern datasets with increasing dimension, researchers have found that the…

Statistics Theory · Mathematics 2020-08-14 Yinqiu He , Bo Meng , Zhenghao Zeng , Gongjun Xu

Quantum mechanics with a generalized uncertainty principle arises through a representation of the commutator $[\hat{x}, \hat{p}] = i f(\hat{p})$. We apply this deformed quantization to free scalar field theory for $f_\pm =1\pm \beta p^2$.…

High Energy Physics - Theory · Physics 2013-02-28 Viqar Husain , Dawood Kothawala , Sanjeev S. Seahra

We study the anisotropic Bianchi I and Bianchi II models in vacuum in the framework of deformed commutation relations (DCRs). Working in a parametrisation of the spatial metric by a volume and two anisotropy variables, we propose modified…

General Relativity and Quantum Cosmology · Physics 2025-10-29 Gabriele Barca , Steffen Gielen

We give an explicit, rigorous framework for calculating quantum probabilities in a model theory of quantum gravity. Specifically, we construct the decoherence functional for the Wheeler-DeWitt quantization of a flat…

General Relativity and Quantum Cosmology · Physics 2011-01-20 David A. Craig , Parampreet Singh

We describe space--time fluctuations by means of small fluctuations of the metric on a given background metric. From a minimally coupled Klein--Gordon equation we obtain within a weak-field approximation up to second order and an averaging…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Ertan Göklü , Claus Lämmerzahl

A Kantowski-Sachs model with a modified quantization prescription is considered. Such quantization rules, inspired by the so-called Generalized Uncertainty Principle (GUP), correspond to a modified commutation relation between…

General Relativity and Quantum Cosmology · Physics 2020-02-06 Pasquale Bosso , Octavio Obregón

We generalize the generalized likelihood ratio (GLR) method through a novel push-out Leibniz integration approach. Extending the conventional push-out likelihood ratio (LR) method, our approach allows the sample space to be…

Methodology · Statistics 2025-05-02 Xingyu Ren , Michael C. Fu