String theory and gravitational waves imprint on microwave background

[ensabah6]

Does it know about gravitational waves and did g-waves leave an imprint on the microwave background?

What does string theory have to say about this and how has string theory changed cosmology in terms of verifiable observational predictions?

 

[atyy]

“In the beginning God created the Heaven and the Earth,
and the Earth was without form, and void;
and the darkness was upon the face of the deep.
And the Breath of God
moved upon the face of the water.”
(Genesis, The Holy Bible).
The most impressive aspect of these verses, for a modern cosmologist, is probably the total absence of any reference to the hot, kinetic, explosive state that one could expect at (or immediately after) the “big bang” deflagration. What is described, instead, is a somewhat quiet, dark, empty state: indeed, we can read about “void”, “darkness”, and “the deep” gives us the idea of something enormously desert and empty. In this static configuration there is at most some small fluctuation (the “Breath”, inducing a ripple on the surface of this vacuum).

M. Gasperini, G. Veneziano
String Theory and Pre-big bang Cosmology
http://arxiv.org/abs/hep-th/0703055

 

[atyy]

http://arxiv.org/abs/0711.1656
The Arrow Of Time In The Landscape
Brett McInnes

Motivated by the Ooguri-Vafa-Verlinde formulation of "creation from nothing" in the context of string theory, we propose that the original universe was created along a spacelike surface with the topology of a torus. Using deep results in global differential geometry, we are able to show that the geometry of this surface had to be non-generic. This geometric "specialness" is communicated to matter through the inflaton. Thus we have a theory of the Arrow which is intrinsically geometric, which incorporates Inflation, and which allows universes in the Landscape to begin with physically acceptable initial conditions.

 

[Chalnoth]

What does string theory have to say about this and how has string theory changed cosmology in terms of verifiable observational predictions?

Well, string theory has inspired a number of ideas which themselves are testable. For instance, string theory has inspired the ekpyrotic model for the birth of regions like our own, where our region would have been born from the collision of two branes in some higher-dimensional space. This idea can be falsified because it predicts that there won't be any of what's called "B-mode polarization", while the traditional inflation models predict quite a lot. This B-mode signal is very difficult to detect, but is the main thrust of the next generation of CMB experiments.

String theory makes no definite predictions here, but it does provide inspiration for more specific models that do.

 

[smallphi]

I bet string theory can derive its own existence LOL