Department of Physics, Princeton University, Princeton,
New Jersey 08544 USA
Abstract:
There is a missing energy problem in cosmology: the total energy density
of the Universe, based on a wide range of observations, is much greater
than the energy density contributed by all baryons, neutrinos, photons,
and dark matter. Deepening this mystery are the recent observations of
type 1a supernovae which suggest that the expansion rate of the Universe
is accelerating. One possible resolution is the existence of a cosmological
constant which fills this energy gap. However, a logical alternative is
``quintessence,'' a time-dependent, spatially inhomogeneous, negative pressure
energy component which drives the cosmic expansion. This lecture will serve
as an introduction to the quintessence cosmological scenario.
