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Several 30-40 minute videos from a great conference on cosmology and the Planck mission results are very much worth watching!
The conference was called The Primordial Universe after Planck and was held in Paris 15-19 Dec.
On the second day, 16 Dec, there was a debate about what the Planck data results mean for inflation. IIRC it was the convenor who reminded the conferees of a bumper sticker he had seen which read "My Karma Ran Over My Dogma"
As introduction to the debate, to get things started, Steinhardt gave a critical review:
http://webcast.in2p3.fr/videos-introduction-_critical_review_of_inflation
Here is the debate ( Steinhardt, Mukhanov, Linde, Brandenberger) that followed Steinhart's (powerful) critique.
http://webcast.in2p3.fr/videos-debate_theoretical_problems_way_forward
Interestingly all four members returned several times to the topic of bounce cosmologies.
Brandenberger was invited to join the panel at the last minute, and he and his group at McGill have been focusing their research for some time on a type of bounce cosmology.
During the 4-way debate, Linde made the point that in order to make a difference people would need to come up with something better than the Inflation scenario and that the way to do that, he thought, was to resolve the "singularity". If the singularity could be removed (for example, he said, by a bounce, or by fluctuation out of an indefinite something else) then that would open up new possibilities which might cure some of the problems with inflation mentioned by Steinhardt.
So the idea kept surfacing. People responded to Steinhardt's critique (by and large) by saying we don't need to abandon the inflation paradigm altogether, we just have to understand it better, what came before it. This could explain, for example, some of the apparent fine-tuning. So there's an interesting trend that manifests itself in different ways.
Incidental note: I sampled a 4-person panel discussion on Future observational prospects and found parts of it interesting. How much farther can we reduce uncertainty? On average spatial curvature for example. How can observations be refined? What might be the consequences of determining, for example, that the overall spatial curvature was positive? The first speaker on the panel addressed this.
The conference was called The Primordial Universe after Planck and was held in Paris 15-19 Dec.
On the second day, 16 Dec, there was a debate about what the Planck data results mean for inflation. IIRC it was the convenor who reminded the conferees of a bumper sticker he had seen which read "My Karma Ran Over My Dogma"
As introduction to the debate, to get things started, Steinhardt gave a critical review:
http://webcast.in2p3.fr/videos-introduction-_critical_review_of_inflation
Here is the debate ( Steinhardt, Mukhanov, Linde, Brandenberger) that followed Steinhart's (powerful) critique.
http://webcast.in2p3.fr/videos-debate_theoretical_problems_way_forward
Interestingly all four members returned several times to the topic of bounce cosmologies.
Brandenberger was invited to join the panel at the last minute, and he and his group at McGill have been focusing their research for some time on a type of bounce cosmology.
BTW at the start of Thursday, 18 Dec, later in the conference, Brandenberger gave a 45 minute review talk on Alternatives, which was followed by P. Peters talk on Bouncing models.
http://webcast.in2p3.fr/videos-bouncing_models
and another by Nelson Pinto-Neto with a similar title: Bouncing models and Planck.
http://webcast.in2p3.fr/videos-bouncing_models
and another by Nelson Pinto-Neto with a similar title: Bouncing models and Planck.
During the 4-way debate, Linde made the point that in order to make a difference people would need to come up with something better than the Inflation scenario and that the way to do that, he thought, was to resolve the "singularity". If the singularity could be removed (for example, he said, by a bounce, or by fluctuation out of an indefinite something else) then that would open up new possibilities which might cure some of the problems with inflation mentioned by Steinhardt.
So the idea kept surfacing. People responded to Steinhardt's critique (by and large) by saying we don't need to abandon the inflation paradigm altogether, we just have to understand it better, what came before it. This could explain, for example, some of the apparent fine-tuning. So there's an interesting trend that manifests itself in different ways.
Incidental note: I sampled a 4-person panel discussion on Future observational prospects and found parts of it interesting. How much farther can we reduce uncertainty? On average spatial curvature for example. How can observations be refined? What might be the consequences of determining, for example, that the overall spatial curvature was positive? The first speaker on the panel addressed this.
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