Monday, April 14, 2014 - 11:15am
Matthias Bartelmann (ZAH/ITA):
"Cosmological constant, dark energy and Lovelock's theorem"
Abstract. In this talk, I shall not present new results, but remind of results achieved by David Lovelock in 1971 and 1972. Reduced to some degree, Lovelock proved that any sufficiently simple metric theory of gravity in four dimensions must equate the energy-momentum tensor to a linear combination of the Einstein and metric tensors. This implies that, under the assumptions made, Einstein's general relativity is unique, that gravity may naturally have a repulsive component and that any such theory must have two coupling constants. One of these constants is the familiar Newtonian gravitational constant, the other is the cosmological constant. I intend to discuss Lovelock's theorems, their implications and their possible consequences for dark energy.