Studies in String Cosmology

In this book we study the problem of moduli
stabilisation in a cosmological context of string
theory. Motivated by the moduli stabilisation
problem, we introduce for the first time chameleon
fields, so named because their masses and values
depend sensitively on the local matter density. We
show that such fields can evade all local tests of
the equivalence principle and we make predictions for
near-future tests of gravity in space while driving
the current phase of cosmic accelerated expansion. We
then study string corrections to racetrack inflation,
a proposal for inflationary dynamics in the context
of flux compactifications. Finally, we study a
truncated low energy effective action that models the
neighbourhood of special points in moduli space, such
as conifold points, where extra massless degrees of
freedom arise. We study moduli dynamics and
stabilisation in this context in a cosmological
background and find surprising variety in field
dynamics including the appearance of chaos. The chaos
aids in our understanding of the behaviour of moduli
near these special points. In particular we find a
viable mechanism for trapping some of the moduli near
these points.

Autorentext
Dr. Weltman, daughter of Ivan and Sheina Weltman, grew up in Johannesburg and Cape Town, South Africa. In 2007 she completed her PhD at Columbia University under the supervision of Professor Brian Greene. After a postdoc at Cambridge University, she is currently faculty at the University of Cape Town, where she completed her undergraduate studies.

Klappentext
In this book we study the problem of moduli stabilisation in a cosmological context of string theory. Motivated by the moduli stabilisation problem, we introduce for the first time chameleon fields, so named because their masses and values depend sensitively on the local matter density. We show that such fields can evade all local tests of the equivalence principle and we make predictions for near-future tests of gravity in space while driving the current phase of cosmic accelerated expansion. We then study string corrections to racetrack inflation, a proposal for inflationary dynamics in the context of flux compactifications. Finally, we study a truncated low energy effective action that models the neighbourhood of special points in moduli space, such as conifold points, where extra massless degrees of freedom arise. We study moduli dynamics and stabilisation in this context in a cosmological background and find surprising variety in field dynamics including the appearance of chaos. The chaos aids in our understanding of the behaviour of moduli near these special points. In particular we find a viable mechanism for trapping some of the moduli near these points.