Format

Send to

Choose Destination
See comment in PubMed Commons below
Phys Rev Lett. 2003 Apr 18;90(15):151301. Epub 2003 Apr 15.

Inflationary spacetimes are incomplete in past directions.

Author information

  • 1Institute of Cosmology, Department of Physics and Astronomy, Tufts University, Medford, MA 02155, USA.

Abstract

Many inflating spacetimes are likely to violate the weak energy condition, a key assumption of singularity theorems. Here we offer a simple kinematical argument, requiring no energy condition, that a cosmological model which is inflating--or just expanding sufficiently fast--must be incomplete in null and timelike past directions. Specifically, we obtain a bound on the integral of the Hubble parameter over a past-directed timelike or null geodesic. Thus inflationary models require physics other than inflation to describe the past boundary of the inflating region of spacetime.

PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for American Physical Society
    Loading ...
    Write to the Help Desk