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We study cosmological tensor perturbations on a quantized background within the hybrid quantization approach. In particular, we consider a flat, homogeneous and isotropic spacetime and small tensor inhomogeneities on it. We truncate the…

General Relativity and Quantum Cosmology · Physics 2016-06-07 Florencia Benítez Martínez , Javier Olmedo

We consider the effects of entanglement in the initial quantum state of scalar and tensor fluctuations during inflation. We allow the gauge-invariant scalar and tensor fluctuations to be entangled in the initial state and compute…

High Energy Physics - Theory · Physics 2017-01-13 Nadia Bolis , Andreas Albrecht , R. Holman

Inflationary cosmological perturbations of quantum-mechanical origin generically interact with all degrees of freedom present in the early Universe. Therefore, they must be viewed as an open quantum system in interaction with an…

Cosmology and Nongalactic Astrophysics · Physics 2018-07-04 Jerome Martin , Vincent Vennin

While the standard, six-parameter, spatially flat $\Lambda$CDM model has been highly successful, certain anomalies in the cosmic microwave background bring out a tension between this model and observations. The statistical significance of…

General Relativity and Quantum Cosmology · Physics 2021-09-21 Abhay Ashtekar , Brajesh Gupt , V. Sreenath

In this paper we consider tensor perturbations produced at a bounce phase in presence of the holonomy corrections. Here bounce phase and holonomy corrections originate from Loop Quantum Cosmology. We re-derive formulas for the corrections…

General Relativity and Quantum Cosmology · Physics 2009-07-09 Jakub Mielczarek

We study the dynamics and predictions of a new emergent-universe model recently derived within Quantum Reduced Loop Gravity and based on the so-called statistical regularization scheme. These effective geometries show a dynamical transition…

General Relativity and Quantum Cosmology · Physics 2019-04-24 Javier Olmedo , Emanuele Alesci

We discuss the evolution of linear perturbations in a quintessence model in which the scalar field is non-minimally coupled to cold dark matter. We consider the effects of this coupling on both cosmic microwave background temperature…

Astrophysics · Physics 2009-02-18 Seokcheon Lee , Guo-Chin Liu , Kin-Wang Ng

Short distance structure of spacetime may show up in the form of high freqency dispersion. Although such dispersion is not locally Lorentz invariant, we show in a scalar field model how it can nevertheless be incorporated into a generally…

High Energy Physics - Theory · Physics 2008-11-26 Ted Jacobson , David Mattingly

We present a new model for the formation of spherically symmetric clusters in an expanding Universe. Both the Universe and the collapsing cluster are governed by the same pressure less fluid equations for which a uniform initial density…

Astrophysics · Physics 2007-05-23 Y. Dabrowski , M. P. Hobson , A. N. Lasenby , C. Doran

The era of precision cosmology has allowed us to accurately determine many important cosmological parameters, in particular via the CMB. Confronting Loop Quantum Cosmology with these observations provides us with a powerful test of the…

General Relativity and Quantum Cosmology · Physics 2012-04-06 Ivan Agullo , Abhay Ashtekar , William Nelson

We examine the quantum loop effects on the single-field inflationary models in a spatially flat Friedmann-Robertson-Walker (FRW) cosmological space-time with a general self-interacting scalar field potential, which is modeled in terms of…

General Relativity and Quantum Cosmology · Physics 2020-02-05 Wei-Can Syu , Da-Shin Lee , Kin-Wang Ng

We examine the constraints cosmological observations can place on any trans-Planckian corrections to the primordial spectrum of perturbations underlying the anisotropies in the Cosmic Microwave Background. We focus on models of…

Astrophysics · Physics 2011-05-12 Richard Easther , William H Kinney , Hiranya Peiris

In order to find the correct theory of quantum gravity, one has to look for observational effects in any candidate theory. Here, we focus on canonical quantum gravity and calculate the quantum-gravitational contributions to the anisotropy…

General Relativity and Quantum Cosmology · Physics 2016-05-20 Manuel Kraemer

We study the effect on the primordial tensor power spectrum of varying the number of e-folds during slow-roll inflation in Loop Quantum Cosmology with a Starobinsky potential. Using the hybrid quantization approach, we derive the effective…

General Relativity and Quantum Cosmology · Physics 2025-11-20 Marceau Henry , Guillermo A. Mena Marugán , Antonio Vicente-Becerril

We explore the consequences of loop quantum cosmology (inverse-volume corrections) in the spectrum of the gravitational waves using the method of the Bogoliubov coefficients. These corrections are taken into account at the background level…

General Relativity and Quantum Cosmology · Physics 2014-01-22 Joao Morais , Mariam Bouhmadi-Lopez , Alfredo B. Henriques

We present a complete analysis of the imprint of tensor anisotropies on the Cosmic Microwave Background for a class of f(R) gravity theories within the PPF-CAMB framework. We derive the equations, both for the cosmological background and…

General Relativity and Quantum Cosmology · Physics 2014-12-22 M. Abdelwahab , A. de la Cruz-Dombriz , P. K. S. Dunsby , B. Mongwane

We present a tentative summary of the many very interesting issues that have been addresses at this workshop, focussing in particular on the perspectives for measuring the polarization power spectra of the Cosmic Microwave Background…

Astrophysics · Physics 2014-10-13 Gianfranco De Zotti , Carlo Burigana , Carlo Baccigalupi

We investigate the anisotropies in the cosmic microwave background in a class of models which possess a positive cosmic energy density but negative pressure, with a constant equation of state w = p/rho < -1. We calculate the temperature and…

Astrophysics · Physics 2009-07-09 A. E. Schulz , Martin White

Quantum effect on the BB-mode correlation spectrum of Cosmic Microwave Background for several inflation models is studied with the BICEP2/Keck Array and Planck joint data. The results do not rule out either single or multi field models of…

General Relativity and Quantum Cosmology · Physics 2017-02-07 N. Malsawmtluangi , P. K. Suresh

We illustrate how it is possible to calculate the quantum gravitational effects on the spectra of primordial scalar/tensor perturbations starting from the canonical, Wheeler-De Witt, approach to quantum cosmology. The composite…

General Relativity and Quantum Cosmology · Physics 2016-12-28 Alexander Y. Kamenshchik , Alessandro Tronconi , Giovanni Venturi