English
Related papers

Related papers: Non-oscillating power spectra in Loop Quantum Cosm…

200 papers

We review that in perturbative string theory, flat, homogeneous and isotropic cosmological evolutions found in no-scale models at the quantum level can enter into "quantum no-scale regimes" (QNSRs). When this is the case, the quantum…

High Energy Physics - Theory · Physics 2018-11-13 Herve Partouche

The leading quantum correction to Einstein-Hilbert Hamiltonian coming from large volume vacuum isotropic loop quantum cosmology, is independent of quantization ambiguity parameters. It is shown here that this correction can be viewed as…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Golam Mortuza Hossain

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

An observer at rest with the expanding universe experiences some extra noise in the quantum vacuum, and so does an accelerated observer in a vacuum at rest (in Minkowski space). The literature mainly focuses on the ideal cases of…

General Relativity and Quantum Cosmology · Physics 2025-01-07 Ziv Landau , Ulf Leonhardt

We compute the predictions for the power spectrum of scalar perturbations from a recent new proposal for the effective Hamiltonian of loop quantum cosmology. The model provides an attractive picture of the early cosmos, in which our…

General Relativity and Quantum Cosmology · Physics 2018-07-06 Ivan Agullo

Closed, singularity-free, inflationary cosmological models have recently been studied in the context of general relativity. Despite their appeal, these so called emergent models suffer from a number of limitations. These include the fact…

Astrophysics · Physics 2009-11-10 David J. Mulryne , Reza Tavakol , James E. Lidsey , George F. R. Ellis

Differences in pressure during expansion and contraction stages in cosmic evolution can result in a hysteresis-like phenomena in non-singular cyclic models sourced with scalar fields. We discuss this phenomena for spatially closed isotropic…

General Relativity and Quantum Cosmology · Physics 2020-04-22 John L. Dupuy , Parampreet Singh

The standard model of cosmology assumes a homogeneous and isotropic universe that undergoes a period of exponential expansion very early on, named inflation. This stretches quantum fluctuations from the onset of inflation to cosmological…

General Relativity and Quantum Cosmology · Physics 2024-10-22 Rita B. Neves

We use the non-equlibrium statistical field theory for classical particles, recently developed by Mazenko and Das and Mazenko, together with the free generating functional we have previously derived for point sets initially correlated in…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-06 Matthias Bartelmann , Felix Fabis , Daniel Berg , Elena Kozlikin , Robert Lilow , Celia Viermann

It has been recently shown that a cosmological bounce model based on Cuscuton gravity does not have any ghosts or curvature instabilities. We explore whether Cuscuton bounce can provide an alternative to inflation for generating near…

General Relativity and Quantum Cosmology · Physics 2021-04-19 J. Leo Kim , Ghazal Geshnizjani

The assumption of asymptotic flatness for isolated astrophysical bodies may be considered an approximation when one considers a cosmological context where a cosmological constant or vacuum energy is present. In this framework we study the…

General Relativity and Quantum Cosmology · Physics 2020-07-29 Bobir Toshmatov , Ozodbek Rahimov , Bobomurat Ahmedov , Daniele Malafarina

We re-examine the process of loop quantization for flat isotropic models in cosmology. In particular, we contrast different inequivalent `loop quantizations' of these simple models through their respective successes and limitations and…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Alejandro Corichi , Parampreet Singh

Current studies about the continuous-variable systems in non-Hermitian quantum mechanics heavily revolved around the singularities in the eigenspectrum by mimicking their discrete-variable counterparts. Discussions over the nonunitary…

Quantum Physics · Physics 2026-04-28 Zhu-yao Jin , Jun Jing

Oscillating solutions to the effective equations of Loop Quantum Cosmology have been suggested for the role of an `eternal seed', providing a possible starting point for the emergent universe scenario. We investigate the stability of a…

High Energy Physics - Theory · Physics 2015-06-19 Audrey T. Mithani , Alexander Vilenkin

We confront various nonsingular bouncing cosmologies with the recently released BICEP2 data and investigate the observational constraints on their parameter space. In particular, within the context of the effective field approach, we…

Cosmology and Nongalactic Astrophysics · Physics 2014-08-19 Yi-Fu Cai , Jerome Quintin , Emmanuel N. Saridakis , Edward Wilson-Ewing

In this paper, we investigate the quantum entanglement induced by phase-space noncommutativity. Both the position-position and momentum-momentum noncommutativity are incorporated to study the entanglement properties of coordinate and…

Quantum Physics · Physics 2024-01-09 Shilpa Nandi , Muklesur Rahaman , Pinaki Patra

We consider a dynamical system of phantom scalar field under exponential potential in background of loop quantum cosmology. In our analysis, there is neither stable node nor repeller unstable node but only two saddle points, hence no Big…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Daris Samart , Burin Gumjudpai

We consider neutrino oscillations in vacuum in the framework of quantum field theory in which neutrino production and detection processes are part of a single Feynman diagram and the corresponding cross section is computed in the standard…

High Energy Physics - Phenomenology · Physics 2020-08-26 Walter Grimus

The quantum evolution equation of Loop Quantum Cosmology (LQC) -- the quantum Hamiltonian constraint -- is a difference equation. We relate the LQC constraint equation in vacuum Bianchi I separable (locally rotationally symmetric) models…

General Relativity and Quantum Cosmology · Physics 2013-01-25 Christine C. Dantas

The fundamental theory and the semiclassical description of loop quantum cosmology (LQC) have been studied in the Friedmann-Robertson-Walker and Bianchi I models. As an extension to include both anisotropy and intrinsic curvature, this…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Dah-Wei Chiou