English

Dynamical Selection of the Primordial Density Fluctuation Amplitude

High Energy Physics - Theory 2011-03-02 v2 Cosmology and Nongalactic Astrophysics

Abstract

In inflationary models, the predicted amplitude of primordial density perturbations Q is much larger than the observed value (~10^{-5}) for natural choices of parameters. To explain the requisite exponential fine-tuning, anthropic selection is often invoked, especially in cases where microphysics is expected to produce a complex energy landscape. By contrast, we find examples of ekpyrotic models based on heterotic M-theory for which dynamical selection naturally favors the observed value of Q.

Keywords

Cite

@article{arxiv.1008.4567,
  title  = {Dynamical Selection of the Primordial Density Fluctuation Amplitude},
  author = {Jean-Luc Lehners and Paul J. Steinhardt},
  journal= {arXiv preprint arXiv:1008.4567},
  year   = {2011}
}

Comments

4 pages; v2: version to be published in PRL

R2 v1 2026-06-21T16:05:39.463Z