2 research outputs found
Non-renormalization for the Liouville wave function
Using an exact functional method, within the framework of the gradient
expansion for the Liouville effective action, we show that the kinetic term for
the Liouville field is not renormalized.Comment: 13 pages Latex, no figure
Tachyon-Dilaton-induced Inflation as an alpha'-resummed String Background
Within the framework of a novel functional method on the world-sheet of the
string, we discuss simple but re-summed (in the Regge slope) inflationary
scenarios in the context of closed Bosonic strings, living in four target-space
dimensions, in the presence of non-trivial tachyon, dilaton and graviton
cosmological backgrounds. The inflationary solutions are argued to guarantee
the vanishing of the corresponding Weyl anomaly coefficients in a given
world-sheet renormalization scheme, thereby ensuring conformal invariance of
the corresponding sigma-model to all orders in the Regge slope. The key
property is the requirement of "homogeneity" of the corresponding Weyl anomaly
coefficients. Inflation entails appropriate relations between the dilaton and
tachyon field configurations, whose form can lead to either a de Sitter vacuum,
incompatible though (due to the cosmic horizons) with the perturbative string
scattering amplitudes, or to cosmic space-times involving brief inflationary
periods, interpolating smoothly between power-law and/or Minkowski Universes.
The latter situation is characterized by well-defined scattering amplitudes,
and is thus compatible with a perturbative string framework. It is this
scenario that we consider a self-consistent ground state in our framework,
which is based on local field redefinitions of background fields.Comment: 35 pages Latex, three eps figures incorporate