Colloquium Seminar Announcement Prof. Joshua Frieman Fermilab and University of Chicago " Probing Dark Energy " Date: Monday, April 4, 2005 55 Roessler Time: 4:10 pm. Abstract: Over the last several years, cosmological observations have pointed with increasing confidence to a recently accelerating universe, yet we have no physical understanding of the dark energy driving this expansion: is it a new form of stress-energy with negative pressure (e.g., the quantum vacuum)? Or does it signal a breakdown of General Relativity on large scales? Or is it due, as very recently suggested, to density inhomogeneities on scales larger than our current horizon? This talk will briefly summarize the current evidence for dark energy, overview some of the theoretical ideas about it, and describe several proposed methods and experiments aimed at probing its nature with greater precision in the coming years.

E-Mail: frieman@fnal.gov
Web Page: http://home.fnal.gov/~frieman/