- #1

MTd2

Gold Member

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I will post just a few papers here:

http://arxiv.org/abs/1003.4660

**Inflation in loop quantum cosmology: Dynamics and spectrum of gravitational waves**

Jakub Mielczarek, Thomas Cailleteau, Julien Grain, Aurelien Barrau

(Submitted on 24 Mar 2010 (v1), last revised 16 Jun 2010 (this version, v2))

Loop quantum cosmology provides an efficient framework to study the evolution of the Universe beyond the classical Big Bang paradigm. Because of holonomy corrections, the singularity is replaced by a "bounce". The dynamics of the background is investigated into the details, as a function of the parameters of the model. In particular, the conditions required for inflation to occur are carefully considered and are shown to be generically met. The propagation of gravitational waves is then investigated in this framework. By both numerical and analytical approaches, the primordial tensor power spectrum is computed for a wide range of parameters. Several interesting features could be observationally probed.

http://arxiv.org/abs/0912.4093

**Loop quantum cosmology and slow roll inflation**

Abhay Ashtekar, David Sloan

(Submitted on 21 Dec 2009 (v1), last revised 2 Oct 2010 (this version, v2))

In loop quantum cosmology (LQC) the big bang is replaced by a quantum bounce which is followed by a robust phase of super-inflation. Rather than growing unboundedly in the past, the Hubble parameter \emph{vanishes} at the bounce and attains a \emph{finite universal maximum} at the end of super-inflation. These novel features lead to an unforeseen implication: in presence of suitable potentials all LQC dynamical trajectories are funneled to conditions which virtually guarantee slow roll inflation with more than 68 e-foldings, {without any input from the pre-big bang regime}. This is in striking contrast to certain results in general relativity, where it is argued that the a priori probability of obtaining a slow roll with 68 or more e-foldings is suppressed by a factor e−204.

http://arxiv.org/abs/1011.5516

**Inflation and Loop Quantum Cosmology**

Aurelien Barrau

(Submitted on 24 Nov 2010)

On the one hand, inflation is an extremely convincing scenario: it solves most cosmological paradoxes and generates fluctuations that became the seeds for the growth of structures. It, however, suffers from a "naturalness" problem: generating initial conditions for inflation is far from easy. On the other hand, loop quantum cosmology is very successful: it solves the Big Bang singularity through a non-perturbative and background-independent quantization of general relativity. It, however, suffers from a key drawback: it is extremely difficult to test. Recent results can let us hope that inflation and LQC could mutually cure those pathologies: LQC seems to naturally generate inflation and inflation could allow us to test LQC.