Phenomenology with fluctuating quantum geometries in loop quantum cosmology

Ivan Agullo, Abhay Ashtekar, Brajesh Gupt

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

The goal of this paper is to probe phenomenological implications of large fluctuations of quantum geometry in the Planck era, using cosmology of the early universe. For the background (Friedmann, Lemaître, Robertson, Walker) quantum geometry, we allow 'widely spread' states in which the relative dispersions are as large as in the Planck regime. By introducing suitable methods to overcome the ensuing conceptual and computational issues, we calculate the power spectrum and the spectral index n s(k) of primordial curvature perturbations. These results generalize the previous work in loop quantum cosmology which focused on those states which were known to remain sharply peaked throughout the Planck regime. Surprisingly, even though the fluctuations we now consider are large, their presence does not add new features to the final and n s(k): within observational error bars, their effect is degenerate with a different freedom in the theory, namely the number of pre-inflationary e-folds between the bounce and the onset of inflation. Therefore, with regard to observational consequences, one can simulate the freedom in the choice of states with large fluctuations in the Planck era using the simpler, sharply peaked states, simply by allowing for different values of NB∗.

Original languageEnglish (US)
Article number074003
JournalClassical and Quantum Gravity
Volume34
Issue number7
DOIs
StatePublished - Mar 7 2017

Fingerprint

phenomenology
cosmology
geometry
power spectra
universe
curvature
perturbation
probes

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy (miscellaneous)

Cite this

@article{d07c8199f8d54cf8b2b468df84f0f1a0,
title = "Phenomenology with fluctuating quantum geometries in loop quantum cosmology",
abstract = "The goal of this paper is to probe phenomenological implications of large fluctuations of quantum geometry in the Planck era, using cosmology of the early universe. For the background (Friedmann, Lema{\^i}tre, Robertson, Walker) quantum geometry, we allow 'widely spread' states in which the relative dispersions are as large as in the Planck regime. By introducing suitable methods to overcome the ensuing conceptual and computational issues, we calculate the power spectrum and the spectral index n s(k) of primordial curvature perturbations. These results generalize the previous work in loop quantum cosmology which focused on those states which were known to remain sharply peaked throughout the Planck regime. Surprisingly, even though the fluctuations we now consider are large, their presence does not add new features to the final and n s(k): within observational error bars, their effect is degenerate with a different freedom in the theory, namely the number of pre-inflationary e-folds between the bounce and the onset of inflation. Therefore, with regard to observational consequences, one can simulate the freedom in the choice of states with large fluctuations in the Planck era using the simpler, sharply peaked states, simply by allowing for different values of NB∗.",
author = "Ivan Agullo and Abhay Ashtekar and Brajesh Gupt",
year = "2017",
month = "3",
day = "7",
doi = "10.1088/1361-6382/aa60ec",
language = "English (US)",
volume = "34",
journal = "Classical and Quantum Gravity",
issn = "0264-9381",
publisher = "IOP Publishing Ltd.",
number = "7",

}

Phenomenology with fluctuating quantum geometries in loop quantum cosmology. / Agullo, Ivan; Ashtekar, Abhay; Gupt, Brajesh.

In: Classical and Quantum Gravity, Vol. 34, No. 7, 074003, 07.03.2017.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Phenomenology with fluctuating quantum geometries in loop quantum cosmology

AU - Agullo, Ivan

AU - Ashtekar, Abhay

AU - Gupt, Brajesh

PY - 2017/3/7

Y1 - 2017/3/7

N2 - The goal of this paper is to probe phenomenological implications of large fluctuations of quantum geometry in the Planck era, using cosmology of the early universe. For the background (Friedmann, Lemaître, Robertson, Walker) quantum geometry, we allow 'widely spread' states in which the relative dispersions are as large as in the Planck regime. By introducing suitable methods to overcome the ensuing conceptual and computational issues, we calculate the power spectrum and the spectral index n s(k) of primordial curvature perturbations. These results generalize the previous work in loop quantum cosmology which focused on those states which were known to remain sharply peaked throughout the Planck regime. Surprisingly, even though the fluctuations we now consider are large, their presence does not add new features to the final and n s(k): within observational error bars, their effect is degenerate with a different freedom in the theory, namely the number of pre-inflationary e-folds between the bounce and the onset of inflation. Therefore, with regard to observational consequences, one can simulate the freedom in the choice of states with large fluctuations in the Planck era using the simpler, sharply peaked states, simply by allowing for different values of NB∗.

AB - The goal of this paper is to probe phenomenological implications of large fluctuations of quantum geometry in the Planck era, using cosmology of the early universe. For the background (Friedmann, Lemaître, Robertson, Walker) quantum geometry, we allow 'widely spread' states in which the relative dispersions are as large as in the Planck regime. By introducing suitable methods to overcome the ensuing conceptual and computational issues, we calculate the power spectrum and the spectral index n s(k) of primordial curvature perturbations. These results generalize the previous work in loop quantum cosmology which focused on those states which were known to remain sharply peaked throughout the Planck regime. Surprisingly, even though the fluctuations we now consider are large, their presence does not add new features to the final and n s(k): within observational error bars, their effect is degenerate with a different freedom in the theory, namely the number of pre-inflationary e-folds between the bounce and the onset of inflation. Therefore, with regard to observational consequences, one can simulate the freedom in the choice of states with large fluctuations in the Planck era using the simpler, sharply peaked states, simply by allowing for different values of NB∗.

UR - http://www.scopus.com/inward/record.url?scp=85015805234&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85015805234&partnerID=8YFLogxK

U2 - 10.1088/1361-6382/aa60ec

DO - 10.1088/1361-6382/aa60ec

M3 - Article

VL - 34

JO - Classical and Quantum Gravity

JF - Classical and Quantum Gravity

SN - 0264-9381

IS - 7

M1 - 074003

ER -