It turns out that this work has a timely significance. In reacting to Martin Bojowald's bounce article in July 2007(adsbygoogle = window.adsbygoogle || []).push({}); Nature Physicsone or more blog personalities spoke as if they understood LQC to deal only with the homogeneous and isotropic case. It doesn't. Current LQC does not only deal with that case. Here is work dealing with the ANisotropic case, and not the first paper either. Some of the crit we heard was based on lack of information.

Actually there are a lot of interesting issues around the quantum-cosmological bounce--much more work needs to be done and IS being done. The effect of inhomogeneities is being investigated and several papers are out about that.

I think it would improve the quality of discussion if we could get the message out concerning recent LQC directions and results.

In any case, Dah-Wei is a UC Berkeley PhD who went to Penn State for postdoc barely a year ago and is already in the thick of things. Kevin V. is a recent Ashtekar PhD who won a coveted European postdoctoral fellowship and chose to enjoy it at Roy Maarten's institute at Portsmouth UK. This work shows how quickly new PhD's can get important results in this field. Congratulations to both.

http://arxiv.org/abs/0707.2548

The behavior of non-linear anisotropies in bouncing Bianchi I models of loop quantum cosmology

Dah-Wei Chiou, Kevin Vandersloot

15 pages, 10 figures

(Submitted on 17 Jul 2007)

"In homogeneous and isotropic loop quantum cosmology, gravity can behave repulsively at Planckian energy densities leading to the replacement of the big bang singularity with a big bounce. Yet in any bouncing scenario it is important to include non-linear effects from anisotropies which typically grow during the collapsing phase. We investigate the dynamics of a Bianchi I anisotropic model within the framework of loop quantum cosmology. Using effective semi-classical equations of motion to study the dynamics, we show that the big bounce is still predicted with only differences in detail arising from the inclusion of anisotropies. We show that the anisotropic shear term grows during the collapsing phase, but remains finite through the bounce. Immediately following the bounce,the anisotropies decayand with the inclusion of matter with equation of state w < +1,the universe isotropizesin the expanding phase."

By the way, on a related subject, Kevin Vandersloot gave what I thought was one of the more interesting contributed talks at the Loops 07.

http://www.matmor.unam.mx/eventos/loops07/cont_abs.html

It appears to confirm BLACK HOLES bounce in certain cases. I will get the abstract.

Kevin Vandersloot:Dynamics of Loop Quantum Schwarzschild Interior· slides (pdf)

"We discuss dynamics of the Schwarzschild interior using an effective semi-classical description of the loop quantization. We will consider the effects of an improved loop quantization using techniques from loop quantum cosmology."

The talk was based on a paper by K.V. with Christian Böhmer (also a postdoc at Portsmouth) which is in preparation.

The paper's title isLoop Quantum Dynamics of Schwarzschild Interior

The conclusions said in part:"Each phenomenological study indicates singularity resolution of Schwarzschild black hole analogously

to LQC results. Detailed consequences dependant on quantization scheme..."

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# Anisotropic LQC bounce: Bianchi-I case (Chiou and Vandersloot)

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