English
Related papers

Related papers: Hybrid loop quantum cosmology and predictions for …

200 papers

A complete numerical calculation of the temperature anisotropies and polarization of the cosmic microwave background (CMB) in the presence of a stochastic helical magnetic field is presented which includes the contributions due to scalar,…

Cosmology and Nongalactic Astrophysics · Physics 2013-05-30 Kerstin E. Kunze

We propose a hybrid quadratic estimator to measure cross correlations between gravitational lensing of the cosmic microwave background (CMB) and differential screening effects arising from fluctuations in the electron column density, such…

Cosmology and Nongalactic Astrophysics · Physics 2019-06-12 Chang Feng , Gilbert Holder

Accurate estimation of cosmological parameters from microwave background anisotropies requires high-accuracy understanding of the cosmological model. Normally, a power-law spectrum of density perturbations is assumed, in which case the…

Astrophysics · Physics 2009-10-30 Edmund J Copeland , Ian J Grivell , Andrew R Liddle

We investigate the scalar mode of perturbation of super inflation in the version of loop quantum cosmology in which the gauge invariant holonomy corrections are considered. Given a background solution, we calculate the power spectrum of the…

General Relativity and Quantum Cosmology · Physics 2015-06-12 Xiao-Jun Yue , Jian-Yang Zhu

We introduce a hybrid classical-quantum algorithm to compute dynamical correlation functions and excitation spectra in many-body quantum systems, with a focus on molecular systems. The method combines classical preparation of a perturbed…

Quantum Physics · Physics 2025-10-30 Alessandro Santini , Stefano Barison , Filippo Vicentini

A general nonperturvative loop quantization procedure for metric modified gravity is reviewed. As an example, this procedure is applied to scalar-tensor theories of gravity. The quantum kinematical framework of these theories is rigorously…

General Relativity and Quantum Cosmology · Physics 2013-04-09 Xiangdong Zhang , Yongge Ma

We derive the primordial power spectrum of density fluctuations in the framework of quantum cosmology. For this purpose we perform a Born-Oppenheimer approximation to the Wheeler-DeWitt equation for an inflationary universe with a scalar…

General Relativity and Quantum Cosmology · Physics 2012-01-17 Claus Kiefer , Manuel Kraemer

In this paper, the scalar and tensor perturbations in the closed algebra approach of loop quantum cosmology are studied. Instead of the distant past in the contracting phase, we choose the moment at which the initial conditions are imposed…

General Relativity and Quantum Cosmology · Physics 2019-06-05 Bao-Fei Li , Tao Zhu , Anzhong Wang , Klaus Kirsten , Gerald Cleaver , Qin Sheng

We study some basic quantum confinement effects through investigation a deformed harmonic oscillator algebra. We show that spatial confinement effects on a quantum harmonic oscillator can be represented by a deformation function within the…

Quantum Physics · Physics 2009-05-20 M. Bagheri Harouni , R. Roknizadeh , M. H. Naderi

We study cosmological perturbations in the framework of Loop Quantum Cosmology, using a hybrid quantization approach and Mukhanov-Sasaki variables. The formulation in terms of these gauge invariants allows one to clarify the independence of…

General Relativity and Quantum Cosmology · Physics 2014-09-17 Laura Castelló Gomar , Mikel Fernández-Méndez , Guillermo A. Mena Marugán , Javier Olmedo

We study cosmological models involving scalar fields coupled to radiation and discuss their effect on the redshift evolution of the cosmic microwave background temperature, focusing on links with varying fundamental constants and dynamical…

Cosmology and Nongalactic Astrophysics · Physics 2014-07-15 A. Avgoustidis , C. J. A. P. Martins , A. M. R. V. L. Monteiro , P. E. Vielzeuf , G. Luzzi

We discuss quantum gravitational loop effects to observable quantities such as curvature power spectrum and primordial non-Gaussianity of cosmic microwave background (CMB) radiation. We first review the previously shown case where one gets…

Cosmology and Nongalactic Astrophysics · Physics 2018-02-21 Sibel Boran , E. O. Kahya

This introductory review is addressed to beginning researchers. Some of the distinguishing features of loop quantum gravity are illustrated through loop quantum cosmology of FRW models. In particular, these examples illustrate: i) how…

General Relativity and Quantum Cosmology · Physics 2010-11-11 Abhay Ashtekar

We extend the phenomenology of loop quantum cosmology (LQC) to second order in perturbations. Our motivation is twofold. On the one hand, since LQC predicts a cosmic bounce that takes place at the Planck scale, the second order…

General Relativity and Quantum Cosmology · Physics 2018-04-04 Ivan Agullo , Boris Bolliet , V. Sreenath

We point out that polarization measurements as planned for the upcoming PLANCK mission can significantly enhance the accuracy of cosmic parameter estimation compared to the temperature anisotropy spectrum alone. In order to illustrate this,…

Astrophysics · Physics 2007-05-23 Pavel Naselsky , Jens Schmalzing , Jesper Sommer-Larsen , Steen Hannested

The spectrum of primordial perturbations obtained by calculating the quantum gravitational corrections to the dynamics of scalar perturbations is compared with Planck 2013 and BICEP2/{\it Keck Array} public data. The quantum gravitational…

General Relativity and Quantum Cosmology · Physics 2015-06-23 Alexander Y. Kamenshchik , Alessandro Tronconi , Giovanni Venturi

These lecture notes cover mainly three connected topics. In the first part we give a detailed treatment of cosmological perturbation theory. The second part is devoted to cosmological inflation and the generation of primordial fluctuations.…

High Energy Physics - Phenomenology · Physics 2009-11-11 Norbert Straumann

We present the full set of power spectra of cosmic microwave background (CMB) temperature and polarization anisotropies due to the coupling between quintessence and pseudoscalar of electromagnetism. This coupling induces the rotation of the…

Astrophysics · Physics 2009-11-11 Guo-Chin Liu , Seokcheon Lee , Kin-Wang Ng

In this paper we consider scalar-tensor theories, allowing for both conformal and disformal couplings to a fluid with a generic equation of state. We derive the effective coupling for both background cosmology and for perturbations in that…

Cosmology and Nongalactic Astrophysics · Physics 2013-05-30 C. van de Bruck , G. Sculthorpe

We investigate the question whether small quantum-gravitational effects can be observed in the anisotropy spectrum of the cosmic microwave background radiation. An observation of such an effect is needed in order to discriminate between…

General Relativity and Quantum Cosmology · Physics 2012-10-15 Claus Kiefer , Manuel Kraemer