PIRSA:C11008 - Challenges for Early Universe Cosmology - 2011PODCAST Subscribe to podcast

Challenges for Early Universe Cosmology


Collection URL: http://pirsa.org/C11008

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PIRSA:11070009  ( MP4 Medium Res , MP3 , PDF ) Which Format?
Observable signatures of anisotropic bubble nucleation
Speaker(s): Michael Salem
Abstract: Our universe may have formed via bubble nucleation in an eternally-inflating background. Furthermore, the background may have a compact dimension---the modulus of which tunnels out of a metastable minimum during bubble nucleation---which subsequently grows to become one of our three large spatial di... read more
Date: 15/07/2011 - 5:30 pm

PIRSA:11070012  ( MP4 Medium Res , MP3 , PDF ) Which Format?
What Happens When Entropy Decreases
Speaker(s): Anthony Aguirre
Abstract: Closed systems never evolve to lower entropy states -- except when they do, which is if one waits a time that is exponential in the entropy change. Thus macroscopic decreases in entropy are 'never' observed. Yet in cosmology there are eternal systems in which downward entropy fluctuations of any mag... read more
Date: 16/07/2011 - 9:00 am

PIRSA:11070006  ( MP4 Medium Res , MP3 , PDF ) Which Format?
Entropy in the Universe
Speaker(s): Don Page
Abstract: "A positive cosmological constant allows arbitrarily many different quantum states, but apparently only if there can be big bangs and/or big crunches. Without any big bang or big crunch, the entropy may be limited by the Gibbons-Hawking entropy of pure deSitter, and the matter entropy might even mor... read more
Date: 16/07/2011 - 9:50 am

PIRSA:11070026  ( MP4 Medium Res , MP3 , PDF ) Which Format?
The Arrow of Time in an Eternal Universe
Speaker(s): Sean B. Carroll
Abstract: If we imagine that the universe is truly eternal, special challenges arise for attempts to solve cosmological fine-tuning problems, especially the low entropy of the early universe. If the space of states is finite, the universe should spend most of its time near equilibrium. If the space of states ... read more
Date: 16/07/2011 - 10:40 am

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