Cosmological perturbations without inflation

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

A particularly attractive feature of inflation is that quantum fluctuations in the inflaton field may have seeded inhomogeneities in the cosmic microwavebackground (CMB) and the formation of large-scale structure. In this paper, we demonstrate that a scalar field with zero active mass, i.e. with an equation of state p + 3p = 0, where p and p are its energy density and pressure, respectively, could also have produced an essentially scale-free fluctuation spectrum, though without inflation. This alternative mechanism is based on the Hollands-Wald concept of a minimum wavelength for the emergence of quantum fluctuations into the semi-classical universe. A cosmology with zero active mass does not have a horizon problem, so it does not need inflation to solve this particular (non) issue. In this picture, the 1°-10° fluctuations in the CMB correspond almost exactly to the Planck length at the Planck time, firmly supporting the view that CMB observations may already be probing trans-Planckian physics.

Original languageEnglish (US)
Article number015011
JournalClassical and Quantum Gravity
Volume34
Issue number1
DOIs
StatePublished - Jan 5 2017

Fingerprint

perturbation
Netherlands
cosmology
horizon
inhomogeneity
equations of state
flux density
universe
scalars
physics
wavelengths

Keywords

  • cosmic perturbations
  • early universe
  • inflation
  • quantum fluctuations

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

Cite this

Cosmological perturbations without inflation. / Melia, Fulvio.

In: Classical and Quantum Gravity, Vol. 34, No. 1, 015011, 05.01.2017.

Research output: Contribution to journalArticle

@article{33c2a31b40c74036b7f2613e2d802084,
title = "Cosmological perturbations without inflation",
abstract = "A particularly attractive feature of inflation is that quantum fluctuations in the inflaton field may have seeded inhomogeneities in the cosmic microwavebackground (CMB) and the formation of large-scale structure. In this paper, we demonstrate that a scalar field with zero active mass, i.e. with an equation of state p + 3p = 0, where p and p are its energy density and pressure, respectively, could also have produced an essentially scale-free fluctuation spectrum, though without inflation. This alternative mechanism is based on the Hollands-Wald concept of a minimum wavelength for the emergence of quantum fluctuations into the semi-classical universe. A cosmology with zero active mass does not have a horizon problem, so it does not need inflation to solve this particular (non) issue. In this picture, the 1°-10° fluctuations in the CMB correspond almost exactly to the Planck length at the Planck time, firmly supporting the view that CMB observations may already be probing trans-Planckian physics.",
keywords = "cosmic perturbations, early universe, inflation, quantum fluctuations",
author = "Fulvio Melia",
year = "2017",
month = "1",
day = "5",
doi = "10.1088/1361-6382/34/1/015011",
language = "English (US)",
volume = "34",
journal = "Classical and Quantum Gravity",
issn = "0264-9381",
publisher = "IOP Publishing Ltd.",
number = "1",

}

TY - JOUR

T1 - Cosmological perturbations without inflation

AU - Melia, Fulvio

PY - 2017/1/5

Y1 - 2017/1/5

N2 - A particularly attractive feature of inflation is that quantum fluctuations in the inflaton field may have seeded inhomogeneities in the cosmic microwavebackground (CMB) and the formation of large-scale structure. In this paper, we demonstrate that a scalar field with zero active mass, i.e. with an equation of state p + 3p = 0, where p and p are its energy density and pressure, respectively, could also have produced an essentially scale-free fluctuation spectrum, though without inflation. This alternative mechanism is based on the Hollands-Wald concept of a minimum wavelength for the emergence of quantum fluctuations into the semi-classical universe. A cosmology with zero active mass does not have a horizon problem, so it does not need inflation to solve this particular (non) issue. In this picture, the 1°-10° fluctuations in the CMB correspond almost exactly to the Planck length at the Planck time, firmly supporting the view that CMB observations may already be probing trans-Planckian physics.

AB - A particularly attractive feature of inflation is that quantum fluctuations in the inflaton field may have seeded inhomogeneities in the cosmic microwavebackground (CMB) and the formation of large-scale structure. In this paper, we demonstrate that a scalar field with zero active mass, i.e. with an equation of state p + 3p = 0, where p and p are its energy density and pressure, respectively, could also have produced an essentially scale-free fluctuation spectrum, though without inflation. This alternative mechanism is based on the Hollands-Wald concept of a minimum wavelength for the emergence of quantum fluctuations into the semi-classical universe. A cosmology with zero active mass does not have a horizon problem, so it does not need inflation to solve this particular (non) issue. In this picture, the 1°-10° fluctuations in the CMB correspond almost exactly to the Planck length at the Planck time, firmly supporting the view that CMB observations may already be probing trans-Planckian physics.

KW - cosmic perturbations

KW - early universe

KW - inflation

KW - quantum fluctuations

UR - http://www.scopus.com/inward/record.url?scp=85006410870&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85006410870&partnerID=8YFLogxK

U2 - 10.1088/1361-6382/34/1/015011

DO - 10.1088/1361-6382/34/1/015011

M3 - Article

AN - SCOPUS:85006410870

VL - 34

JO - Classical and Quantum Gravity

JF - Classical and Quantum Gravity

SN - 0264-9381

IS - 1

M1 - 015011

ER -