Cosmological solutions in string theories

  title={Cosmological solutions in string theories},
  author={H. Q. Lu and Sudipta Mukherji and C N Pope and K.-W. Xu},
  journal={Physical Review D},
We obtain a large class of cosmological solutions in the toroidally compactified low-energy limits of string theories in D dimensions. We consider solutions where a p-dimensional subset of the spatial coordinates, parametrizing a flat space, a sphere, or a hyperboloid, describes the spatial sections of the physically observed Universe. The equations of motion reduce to Liouville or SL(N+1,R) Toda equations, which are exactly solvable. We study some of the cases in detail, and find that under… 
Resolution of cosmological singularities in string theory
We show that a class of (3+1)-dimensional Friedmann-Robertson-Walker cosmologies can be embedded within a variety of solutions of string theory. In some realizations, the apparent singularities
Dynamics of intersecting brane systems ? Classification and their applications
We present dynamical intersecting brane solutions in higher-dimensional gravitational theory coupled to dilaton and several forms. Assuming the forms of metric, form fields, and dilaton field, we
Remarks on Tachyon Driven Cosmology
We begin by reviewing the results on the decay of unstable D-branes in type II string theory, and the open–closed string duality proposal that arises from these studies. We then apply this proposal
Cosmological solutions, p -branes, and the Wheeler-DeWitt equation
The low energy effective actions which arise from string theory or M-theory are considered in the cosmological context, where the graviton, dilaton and antisymmetric tensor field strengths depend
String and M-theory cosmological solutions with Ramond forms
Accelerating universes in string theory via field redefinition
We study cosmological solutions in the effective heterotic string theory with α′-correction terms in the string frame. It is pointed out that the effective theory has an ambiguity via field
Qualitative analysis of anisotropic and curved string cosmologies
A complete qualitative study of the dynamics of string cosmologies is presented for the class of isotopic curvature universes. These models are of Bianchi types I, V and IX and reduce to the general


Cosmological solutions of type II string theory
Low energy effective string cosmology.
We give the general analytic solutions derived from the low energy string effective action for four-dimensional Friedmann-Robertson-Walker models with a dilaton and antisymmetric tensor field,
Stringy Toda cosmologies
We discuss a particular stringy modular cosmology with two axion fields in seven space-time dimensions, decomposable as a time and two flat three-spaces. The effective equations of motion for the
On the Cosmology and Symmetry of Dilaton-Axion Gravity
A global O$(2,2)$ symmetry is found in the Brans-Dicke theory of gravity when the dilaton is coupled to axion and moduli fields. The symmetry is broken if a cosmological constant is introduced.
p-brane solitons in maximal supergravities
We study the general form of the equations for isotropic single-scalar, multi-scalar and dyonic p-branes in superstring theory and M-theory, and show that they can be cast into the form of Liouville,