Oak Ridge National Laboratory

Physics Division

Physics Division Seminars

Physics Division Seminars bring us speakers on a variety of physics related subjects. Usually these are held in the Building 6008 large Conference Room, at 3:00 pm on the chosen day, but times and locations may vary. For more information, contact our seminar chairman,

Alfredo Galindo-Uribarri
Tel (Office): (865) 574-6124  (FAX): (865) 574-1268


Tue., April 14, 2009, at 11:00 a.m. (refreshments at 10:40 a.m.)

Dark Energy: The Cosmological Constant in Disguise

Stephon Alexander, The Koshland Center for Integrated Sciences, Haverford College, Haverford, PA
Building 6008 Conference Room

Recent cosmological observations have reached the conclusion that our universe is undergoing an accelerated expansion. A mysterious unknown substance called Dark Energy is needed to drive this acceleration. This dark energy resurrects the infamous cosmological constant problem back into theoretical physics. Moreover, the best paradigm which solves the problems of the standard big bang cosmology is an early phase of rapid acceleration (cosmic inflation), requiring a much larger value of the same dark energy substance. The existence and nature of dark energy has surprised and mystified cosmologists. In this colloquium I will review cosmic inflation and the dark energy/cosmological problem and discuss the challenges that they bring to theoretical physics. Finally, I will provide a novel mechanism which potentially connects dark energy to neutrino vacuum oscillations.