COT4 - Nonsingular Cosmology - Inflation |
Speaker_ |
Melnikov, Vitaly |
Talk _ |
Non-singular solutions in multidimensional cosmology. |
Abstract _ |
Using developed earlier our methods for multidimensional models a family of cosmological solutions in D-dimensional model with two sets of scalar fields ö1 and ö2 and exponential potential depending upon ö1 are considered. The solutions are defined on a product of n Ricci-flat spaces.The fields from ö1 have positive kinetic terms and ö2 are "phantom" fields with negative kinetic terms. For vector coupling constant obeying 0<ë<(D-1)/(D-2) a subclass of non-singular solutions is singled out. They are regular for all values of synchronous time t. For ë2<1/(D-2)we get an asymptotically accelerated and isotropic expansion for large values of t. As a particular case a family of Bianchi-I cosmological solutions in D= 4 with two scalar fields ö and ø and exponential potential depending upon ö is considered. ö is usual and ø is a "phantom" field.For ë2 < 3/2 a subclass of solutions with bouncing of the volume scale factor is singled out.These solutions are regular for all values of t and possess an isotropization behaviour for large t. For ë2 < 1/2 we get an asymptotically accelerated and isotropic expansion for large t. It is shown that anisotropies are separated, i.e. any anisotropical solution may be obtained from the isotropical one by deformation of scale factors and suitable increasing of "phantom" scalar charge. Other non-singular solutions in diverse dimensions are discussed. |