3 research outputs found
The dynamics of coset dimensional reduction
The evolution of multiple scalar fields in cosmology has been much studied,
particularly when the potential is formed from a series of exponentials. For a
certain subclass of such systems it is possible to get `assisted` behaviour,
where the presence of multiple terms in the potential effectively makes it
shallower than the individual terms indicate. It is also known that when
compactifying on coset spaces one can achieve a consistent truncation to an
effective theory which contains many exponential terms, however, if there are
too many exponentials then exact scaling solutions do not exist. In this paper
we study the potentials arising from such compactifications of eleven
dimensional supergravity and analyse the regions of parameter space which could
lead to scaling behaviour.Comment: 27 pages, 4 figures; added citation
Cosmology with Twisted Tori
We consider the cosmological role of the scalar fields generated by the
compactification of 11-dimensional Einstein gravity on a 7D elliptic twisted
torus, which has the attractive features of giving rise to a positive
semi-definite potential, and partially fixing the moduli. This compactification
is therefore relevant for low energy M-theory, 11D supergravity. We find that
slow-roll inflation with the moduli is not possible, but that there is a novel
scaling solution in Friedmann cosmologies in which the massive moduli oscillate
but maintain a constant energy density relative to the background barotropic
fluid