The effects of multiple modes and reduced symmetry on the rapidity and robustness of slow contraction

Anna Ijjas, Frans Pretorius, Paul J. Steinhardt, Andrew P. Sullivan

Research output: Contribution to journalArticlepeer-review

Abstract

We demonstrate that the rapidity and robustness of slow contraction in homogenizing and flattening the universe found in simulations in which the initial conditions were restricted to non-perturbative variations described by a single Fourier mode along only a single spatial direction are in general enhanced if the initial variations are along two spatial directions, include multiple modes, and thereby have reduced symmetry. Particularly significant are shear effects that only become possible when variations are allowed along two or more spatial dimensions. Based on the numerical results, we conjecture that the counterintuitive enhancement occurs because more degrees of freedom are activated which drive spacetime away from an unstable Kasner fixed point and towards the stable Friedmann-Robertson-Walker fixed point.

Original languageEnglish (US)
Article number136490
JournalPhysics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
Volume820
DOIs
StatePublished - Sep 10 2021

All Science Journal Classification (ASJC) codes

  • Nuclear and High Energy Physics

Keywords

  • Bouncing/cyclic cosmology
  • Homogeneity
  • Isotropy
  • Mode coupling
  • Numerical relativity
  • Slow contraction

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