IPB Colloquium by Nemanja Kaloper

On June 12, 2015, at 13:00, in the hall "Zvonko Marić" of the Institute of Physics Belgrade, Prof. Dr. Nemanja Kaloper (Department of Physics, University of California - UC Davis) will present a colloquium talk entitled:


Abstract: Curiously, one can state the cosmological constant's implications for modern physics by a wordplay on the title of the famous Gauguin painting on exhibit in the Museum of Fine Arts in Boston: "Where does the Universe come from? What is the Universe? Where is the Universe going?". These questions appear to be distinct and independent queries about the past, present and future of the universe. Yet,our attempts to answer them all share a crucial common ingredient: vacuum energy, or cosmological constant. Indeed, vacuum energy plays key role in driving inflation, in dominating the present universe, and if it is here to stay forever, in fully controlling the cosmic future. Yet we still do not comprehend vacuum energy dynamics, and we continue to stumble searching for a mechanism to control its scale. In this talk I will discuss the problems, and go over a recent proposal how to sequester vacuum energy by a very minimal modification of gravitational dynamics. The implications of the mechanism are rather surprising: if it is the way how nature works, then the universe must end: it must collapse some time in the future, the current dark energy which dominates is just a transient, and its spatial geometry is not flat, but instead a three dimensional sphere. Therefore the cosmic future may be inextricably linked to its beginnings by this 'cosmic symmetry'.