No open or flat bouncing cosmologies in Einstein gravity

@article{Parikh2015NoOO,
  title={No open or flat bouncing cosmologies in Einstein gravity},
  author={Maulik Parikh},
  journal={Journal of High Energy Physics},
  year={2015},
  volume={2015},
  pages={1-11}
}
  • M. Parikh
  • Published 19 January 2015
  • Physics
  • Journal of High Energy Physics
A bstractWe show that, to first approximation, strings cannot propagate in bouncing open or flat Friedmann-Robertson-Walker universes. Specifically, the Virasoro constraint translates to the Ricci convergence condition in spacetime at leading order in the alpha-prime expansion. Thus one must go beyond minimally-coupled classical Einstein gravity in order to find bounce solutions that could be consistent with string theory. We map out some remaining possibilities for finding string-compatible… 
View on Springer
link.springer.com
7 Citations
Background Citations
4

7 Citations

Constraining de Sitter Space in String Theory.

It is argued that the heterotic string does not have classical vacua corresponding to de Sitter space-times of dimension four or higher, and suggests that the genericity arguments used in string landscape discussions should be viewed with caution.

On coupling NEC-violating matter to gravity

Two Roads to the Null Energy Condition

The null energy condition has sweeping consequences in general relativity. I argue here that it has been misunderstood as a property exclusively of matter, when in fact it arises only in a theory of…

0 D ec 2 01 5 Two Roads to the Null Energy Condition

The null energy condition has sweeping consequences in general relativity. I argue here that it has been misunderstood as a property exclusively of matter, when in fact it arises only in a theory of…

Emergence of Spacetime: From Entanglement to Einstein

Here I develop the connection between thermodynamics, entanglement, and gravity. I begin by showing that the classical null energy condition (NEC) can arise as a consequence of the second law of…

Thermodynamic Origin of the Null Energy Condition

We derive the classical null energy condition, understood as a constraint on the Ricci tensor, from the second law of thermodynamics applied locally to Bekenstein-Hawking entropy associated with…

Superbounce and Loop Quantum Ekpyrotic Cosmologies from Modified Gravity: $F(R)$, $F(G)$ and $F(T)$ Theories

References

SHOWING 1-10 OF 33 REFERENCES

Cosmological super-bounce

We study a model for a non-singular cosmic bounce in N=1 supergravity, based on supergravity versions of the ghost condensate and cubic Galileon scalar field theories. The bounce is preceded by an…

Bouncing cosmologies in massive gravity on de Sitter

In the framework of massive gravity with a de Sitter reference metric, we study homogeneous and isotropic solutions with positive spatial curvature. Remarkably, we find that bounces can occur when…

G-bounce

We present a wide class of models which realise a bounce in a spatially flat Friedmann universe in standard General Relativity. The key ingredient of the theories we consider is a noncanonical,…

Bouncing universe with Quintom matter

The bouncing universe provides a possible solution to the Big Bang singularity problem. In this paper we study the bouncing solution in the universe dominated by the Quintom matter with an equation…

Matter bounce cosmology with the f(T) gravity

We show that the f(T) gravitational paradigm, in which gravity is described by an arbitrary function of the torsion scalar, can provide a mechanism for realizing bouncing cosmologies, thereby…

A Matter Bounce By Means of Ghost Condensation

Assuming the existence of a scalar field which undergoes "ghost condensation" and which has a suitably chosen potential, it is possible to obtain a non-singular bouncing cosmology in the presence of…

Bouncing universes in string-inspired gravity

We consider the effects on cosmology of higher derivative modifications of gravity that make it asymptotically free without introducing ghosts. The weakening of gravity at short distances allows…

Constraints on string cosmology

String theory contains sources like orientifold planes that support higher derivative interactions. These interactions make static flux compactifications possible which are forbidden in supergravity.…

Bouncing Cosmologies

An obstacle to creating a universe in the laboratory