Gravitational Fluctuations as an Alternative to Inflation
arXiv:1807.10704 · doi:10.3390/universe5010031
Abstract
The ability to reproduce the observed matter power spectrum to high accuracy is often considered as a triumph of inflation. In this work, we explore an alternative explanation for the power spectrum based on nonperturbative quantum field-theoretical methods applied to Einstein's gravity, instead of ones based on inflation models. In particular the power spectral index, which governs the slope on the graph, can be related to critical scaling exponents derived from the Wilson renormalization group analysis. We find that the derived value fits favorably with the Sloan Digital Sky Survey telescope data. We then make use of the transfer functions, based only on the Boltzmann equations which describe states out of equilibrium, and Einstein's General Relativity, to extrapolate the power spectrum to the Cosmic Microwave Background (CMB) regime. We observe that the results fit rather well with current data. Our approach contrasts with the conventional explanation which uses inflation to generate the scale invariant Harrison-Zel'dovich spectrum on CMB scales, and uses the transfer function to extrapolate it to galaxy regime. The results we present here only assume quantum field theory and Einstein's Gravity, and hence provide a competing explanation of the power spectrum, without relying on the assumptions usually associated with inflationary models. At the end, we also outline several testable predictions in this picture that deviate from the conventional picture of inflation, and which hopefully will become verifiable in the near future with increasingly accurate measurements.
arXiv comment33 pages, 6 figures. One figure added following the July 2018 release of new Planck data. Typos fixed, more references added. Paper now conforms to the published version
References in corpus (48)
- Planck 2015 results. XIII. Cosmological parameters
- The 3D power spectrum of galaxies from the SDSS
- Planck 2018 results. I. Overview and the cosmological legacy of Planck
- Nonperturbative Evolution Equation for Quantum Gravity
- Pre-Big-Bang in String Cosmology
- Renormalons
- Cosmological perturbations
- A Cyclic Model of the Universe
- Fixed points of quantum gravity
- Inflationary paradigm in trouble after Planck2013
- Further evidence for asymptotic safety of quantum gravity
- What does inflation really predict?
- Inflationary paradigm after Planck 2013
- Fixed points of quantum gravity in extra dimensions
- Bimetric Renormalization Group Flows in Quantum Einstein Gravity
- Scaling Exponents in Quantum Gravity near Two Dimensions
- The No-Boundary Measure of the Universe
- Inflationary schism after Planck2013
- The clustering of the SDSS-IV extended Baryon Oscillation Spectroscopic Survey DR14 quasar sample: structure growth rate measurement from the anisotropic quasar power spectrum in the redshift range
- Separating the Early Universe from the Late Universe: cosmological parameter estimation beyond the black box
- En route to Background Independence: Broken split-symmetry, and how to restore it with bi-metric average actions
- Generalized Parametrization Dependence in Quantum Gravity
- Renormalization Group Equation and scaling solutions for f(R) gravity in exponential parametrization
- The Richness-Dependent Cluster Correlation Function: Early SDSS Data
- Consistent closure of renormalization group flow equations in quantum gravity
- Nonlocal Effective Gravitational Field Equations and the Running of Newton's G
- Renormalisation of Newton's constant
- Inflationary predictions for scalar and tensor fluctuations reconsidered
- Pre-big bang bubbles from the gravitational instability of generic string vacua
- Gauges and functional measures in quantum gravity I: Einstein theory
- On the Gravitational Scaling Dimensions
- The role of Background Independence for Asymptotic Safety in Quantum Einstein Gravity
- Two-loop Prediction for Scaling Exponents in (2 + ε)-dimensional Quantum Gravity
- The SDSS Galaxy Angular Two-Point Correlation Function
- The evolution of clustering length, large-scale bias and host halo mass at 2<z<5 in the VIMOS Ultra Deep Survey (VUDS)
- Non-Perturbative Gravity and the Spin of the Lattice Graviton
- Large Scale Structure of the Universe
- Scaling Exponents for Lattice Quantum Gravity in Four Dimensions
- Invariant Correlations in Simplicial Gravity
- Asymptotic safety and the cosmological constant
- Quantum Gravity in Large Dimensions
- Wheeler-DeWitt Equation in 2 + 1 Dimensions
- Inconsistencies from a Running Cosmological Constant
- Scaling Behavior of Ricci Curvature at Short Distance near Two Dimensions
- Critical scaling in quantum gravity from the renormalisation group
- Scale-Dependent Newton's Constant G in the Conformal Newtonian Gauge
- Cosmological Density Perturbations with a Scale-Dependent Newton's G
- Issues for the Next Generation of Galaxy Surveys