Tufts/CfA/MIT Cosmology Seminar, at Tufts:

Tuesday, March 27, 2007
2:30 pm
Robinson Hall, Room 250
Refreshments at 2:00 in Knipp Library, Room 251

"The Liberal Landscape: From the Weakless Universe to the Causal Entropic Principle"


Roni Harnik
Stanford

Abstract:

Anthropic arguments have been proposed as explanations of the two biggest hierarchy problems we face today, The electroweak (EW) hierarchy and the cosmological constant (CC). In order for anthropic arguments to make correct predictions for both of these problems, conservative assumptions must be made. One must only consider a conservative landscape where a couple of parameters are allowed to vary. One also must make strong assumptions about what form observers may take. Inspired by the diversity of the string landscape I will take a liberal view of the landscape and consider the implications of this new view on both hierarchy problems. For the EW hierarchy I will present the `Weakless Universe', a hypothetical counterexample for a Universe very similar to ours but without weak interactions. As for the CC, I will present the Causal Entropic Principle, weighting vacua by entropy production in the causal diamond, as a promising approach to making predictions on the landscape.

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