10 research outputs found
Stationary Universe
If the Universe contains at least one inflationary domain with a sufficiently
large and homogeneous scalar field, then this domain permanently produces new
inflationary domains of all possible types. We show that under certain
conditions this process of the self-reproduction of the Universe can be
described by a stationary distribution of probability, which means that the
fraction of the physical volume of the Universe in a state with given
properties (with given values of fields, with a given density of matter, etc.)
does not depend on time. This represents a strong deviation of inflationary
cosmology from the standard Big Bang paradigm.Comment: 12 pages, SU-ITP-93-9 (few misprints removed
String Thermalization at a Black Hole Horizon
Susskind has recently shown that a relativistic string approaching the event
horizon of a black hole spreads in both the transverse and longitudinal
directions in the reference frame of an outside observer. The transverse
spreading can be described as a branching diffusion of wee string bits. This
stochastic process provides a mechanism for thermalizing the quantum state of
the string as it spreads across the stretched horizon.Comment: 14 pages, latex, SU-ITP-94-4, NSF-ITP-94-1
Inflation with
We discuss various models of inflationary universe with . A
homogeneous universe with may appear due to creation of the
universe "from nothing" in the theories where the effective potential becomes
very steep at large , or in the theories where the inflaton field
nonminimally couples to gravity. Inflation with generally requires
intermediate first order phase transition with the bubble formation, and with a
second stage of inflation inside the bubble. It is possible to realize this
scenario in the context of a theory of one scalar field, but typically it
requires artificially bent effective potentials and/or nonminimal kinetic
terms. It is much easier to obtain an open universe in the models involving two
scalar fields. However, these models have their own specific problems. We
propose three different models of this type which can describe an open
homogeneous inflationary universe.Comment: 29 pages, LaTeX, parameters of one of the models are slightly
modifie
From the Big Bang Theory to the Theory of a Stationary Universe
We consider chaotic inflation in the theories with the effective potentials
phi^n and e^{\alpha\phi}. In such theories inflationary domains containing
sufficiently large and homogeneous scalar field \phi permanently produce new
inflationary domains of a similar type. We show that under certain conditions
this process of the self-reproduction of the Universe can be described by a
stationary distribution of probability, which means that the fraction of the
physical volume of the Universe in a state with given properties (with given
values of fields, with a given density of matter, etc.) does not depend on
time, both at the stage of inflation and after it. This represents a strong
deviation of inflationary cosmology from the standard Big Bang paradigm. We
compare our approach with other approaches to quantum cosmology, and illustrate
some of the general conclusions mentioned above with the results of a computer
simulation of stochastic processes in the inflationary Universe.Comment: No changes to the file, but original figures are included. They
substantially help to understand this paper, as well as eternal inflation in
general, and what is now called the "multiverse" and the "string theory
landscape." High quality figures can be found at
http://www.stanford.edu/~alinde/LLMbigfigs