Skip to main content
OSTI.GOVU.S. Department of Energy Office of Scientific and Technical Information
U.S. Department of Energy
Office of Scientific and Technical Information
 

Smoothing and flattening the universe through slow contraction versus inflation

Journal Article · · Journal of Cosmology and Astroparticle Physics
 [1];  [2];  [3];  [4]
  1. New York University, NY (United States)
  2. Princeton University, NJ (United States); Harvard University, Cambridge MA (United States)
  3. Oakland University, Rochester, MI (United States)
  4. Friedrich-Schiller-Universität Jena (Germany)
+ Show Author Affiliations
In a systematic study, we use an equivalent pair of improved numerical relativity codes based on a tetrad-formulation of the classical Einstein-scalar field equations to examine whether slow contraction or inflation (or both) can resolve the homogeneity, isotropy and flatness problems. Our finding, based on a set of gauge/frame invariant diagnostics and the models considered, is that slow contraction robustly and rapidly smooths and flattens spacetime beginning from initial conditions that are outside the perturbative regime of the flat Friedmann-Robertson-Walker metric, whereas inflation fails these tests. We present new numerical evidence supporting the conjecture that the combination of ultralocal evolution and an effective equation-of-state with pressure much greater than energy density is the key to having robust and rapid smoothing. The opposite of ultralocality occurs in expanding spacetimes, which is the leading obstruction to smoothing following a big bang.
Research Organization:
Princeton University, NJ (United States)
Sponsoring Organization:
National Science Foundation (NSF); Simons Foundation; USDOE Office of Science (SC), High Energy Physics (HEP)
Grant/Contract Number:
FG02-91ER40671; SC0007968
OSTI ID:
2484172
Journal Information:
Journal of Cosmology and Astroparticle Physics, Journal Name: Journal of Cosmology and Astroparticle Physics Journal Issue: 07 Vol. 2024; ISSN 1475-7516
Publisher:
Institute of Physics (IOP)Copyright Statement
Country of Publication:
United States
Language:
English

References (27)

Initial conditions for inflation journal May 1992
Fully stable cosmological solutions with a non-singular classical bounce journal January 2017
Supersmoothing through slow contraction journal September 2020
The effects of multiple modes and reduced symmetry on the rapidity and robustness of slow contraction journal September 2021
Initial conditions problem in cosmological inflation revisited journal August 2023
Oscillatory approach to a singular point in the relativistic cosmology journal July 1970
Beginning inflation in an inhomogeneous universe journal September 2016
Robustness of inflation to inhomogeneous initial conditions journal September 2017
Robustness of inflation to large tensor perturbations journal May 2018
The effects of potential shape on inhomogeneous inflation journal May 2020
Robustness of slow contraction to cosmic initial conditions journal August 2020
Sourcing curvature modes with entropy perturbations in non-singular bouncing cosmologies journal June 2021
Ultralocality and slow contraction journal June 2021
Dynamical attractors in contracting spacetimes dominated by kinetically coupled scalar fields journal December 2021
The robustness of slow contraction and the shape of the scalar field potential journal August 2022
Gauge/frame invariant variables for the numerical relativity study of cosmological spacetimes journal June 2023
Starting inflation from inhomogeneous initial conditions with momentum journal October 2023
Spike behavior in the approach to spacetime singularities journal December 2020
Inhomogeneous preinflation across Hubble scales in full general relativity journal April 2021
Nearly scale-invariant curvature modes from entropy perturbations during the graceful exit phase journal May 2021
Evolution to a smooth universe in an ekpyrotic contracting phase with w > 1 journal October 2008
Spikes in the mixmaster regime of G 2 cosmologies journal June 2009
Classically Stable Nonsingular Cosmological Bounces journal September 2016
Cosmological Bounces Induced by a Fermion Condensate journal August 2023
Gravitational Degrees of Freedom and the Initial-Value Problem journal June 1971
Inhomogeneity and the onset of inflation journal June 1990
The Singularity in Generic Gravitational Collapse is Spacelike, Local and Oscillatory journal June 1998

Similar Records

Ultralocality and slow contraction
Journal Article · Tue Jun 01 00:00:00 EDT 2021 · Journal of Cosmology and Astroparticle Physics · OSTI ID:1850009
Dynamical attractors in contracting spacetimes dominated by kinetically coupled scalar fields
Journal Article · Sun Dec 12 19:00:00 EST 2021 · Journal of Cosmology and Astroparticle Physics · OSTI ID:1979348

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
alternatives to inflation
cosmic singularity
inflation
physics of the early universe