<b>High Energy-Astrophysics</b><br><i>Is Cosmic Acceleration Telling Us Something About Gravity?</i>
Speaker: Mark Trodden (University of Pennsylvania)
Professor Trodden will discuss the cosmological constraints on theories in which there exists a nontrivial coupling between the dark matter sector and the sector responsible for the acceleration of the universe, in light of the most recent supernovae, large scale structure and cosmic microwave background data. He will further show that such theories can possess an adiabatic regime in which the quintessence field always sits at the minimum of its effective potential, which is set by the local dark matter density. If the coupling strength is much larger than gravitational, then Professor Trodden will demonstrate that the adiabatic regime is always subject to an instability, constraining a large class of models.