Lecturer: Prof. Tom Banks
Affiliation: University of California, Santa Cruz
and Rutgers University
Abstract:
The theory of Holographic Space Time
associates localized excitations in the bulk
of a causal diamond, with CONSTRAINTS
on the fundamental degrees of freedom
living on the holographic screen of the
diamond. In asymptotically flat or dS space-
time the energy of an excitation is directly
proportional to the number of constraints
imposed. Applied to cosmology, these ideas
show that the most generic initial conditions
lead to a space-time with no localized
excitations. The metric is a flat FRW with a
two component equation of state p = \pm
\rho. Maximal entropy initial conditions
WITH localized excitations lead to space-
times containing a collection of black holes
in an asymptotically dS space. If the black
hole gas is not fairly homogeneous and
isotropic, we end up with a few large black
holes, which decay into radiation useless for
forming organized structures.
A uniform gas eventually produces a
radiation dominated universe. If the model
contains a dark matter candidate, it can
have galaxy like structures. The uniform gas
of black holes when they are outside the
apparent horizon, behave like independent
horizon volumes of an inflationary universe.
Since they are finite quantum systems,
there are fluctuations in both their mass and
angular momentum. These lead to the
primordial scalar and tensor fluctuations. An
additional distribution of tensor fluctuations
is produced from black hole decays into
gravitons, later in the history of the universe.
With appropriate choice of slow roll metric,
the model can reproduce current data on
scalar fluctuations.
It makes distinctive predictions for tensor
fluctuations.