• Corpus ID: 250264825

On the past-completeness of inflationary spacetimes

@inproceedings{Lesnefsky2022OnTP,
  title={On the past-completeness of inflationary spacetimes},
  author={Joseph Lesnefsky and Damien A Easson and Paul C. W. Davies},
  year={2022}
}
We discuss the question of whether or not inflationary spacetimes can be geodesically complete in the infinite past. Geodesic completeness is a necessary condition for averting an initial singularity during eternal inflation. It is frequently argued that cosmological models which are expanding sufficiently fast (having average Hubble expansion rate H avg > 0 ) must be incomplete in null and timelike past directions. This well-known conjecture relies on specific bounds on the integral of the Hubble… 

Figures from this paper

References

SHOWING 1-10 OF 54 REFERENCES

Inflationary spacetimes are incomplete in past directions.

A simple kinematical argument is offered that a cosmological model which is inflating--or just expanding sufficiently fast--must be incomplete in null and timelike past directions, and a bound on the integral of the Hubble parameter over a past-directed timelikes or null geodesic is obtained.

Singularities in FLRW spacetimes

A simple harmonic universe

A bstractWe explore simple but novel bouncing solutions of general relativity that avoid singularities. These solutions require curvature k = +1, and are supported by a negative cosmological term and

The Phantom of the New Oscillatory Cosmological Phase

We study a recently proposed new cosmological phase where a scalar field moves periodically in an expanding spatially-flat Friedmann universe. This phase corresponds to a limiting cycle of the

Quantum instability of the emergent universe

We perform a semi-classical analysis of the Emergent Universe scenario for inflation. Fixing the background, and taking the inflaton to be homogenous, we cast the inflaton’s evolution as a

Galilean Genesis: An Alternative to inflation

We propose a novel cosmological scenario, in which standard inflation is replaced by an expanding phase with a drastic violation of the Null Energy Condition (NEC): >> H2. The model is based on the

Oscillatory attractors: a new cosmological phase

In expanding FRW spacetimes, it is usually the case that homogeneous scalar fields redshift and their amplitudes approach limiting values: Hubble friction usually ensures that the field relaxes to

Brane gases in the early Universe

Over the past decade it has become clear that fundamental strings are not the only fundamental degrees of freedom in string theory. D-branes are also part of the spectrum of fundamental states. In

Inflationary universe: A possible solution to the horizon and flatness problems

The standard model of hot big-bang cosmology requires initial conditions which are problematic in two ways: (1) The early universe is assumed to be highly homogeneous, in spite of the fact that

Eternal inflation and its implications

I summarize the arguments that strongly suggest that our universe is the product of inflation. The mechanisms that lead to eternal inflation in both new and chaotic models are described. Although the
...