ULTRAMETRIC EXTRADIMENSIONS AND TACHYONIC COSMOLOGY

We consider (4+D)-dimensional Kaluza-Klein cosmological model with two scaling factors. One of the scaling factors corresponds to the D-dimensional internal space, and second one to the 4-dimensional universe. In standard quantum cosmology, i.e. over the fleld of real numbers R it leads to dynamical compactiflcation of additional dimen- sions and to the accelerating evolution of 4-dimensional universe We construct corresponding p-adic quantum model and explore existence of its p-adic ground state. In addition, we explore evolution of this model and a possibility for its adelic generalization. It is necessary for the further investigation of space-time discreteness at very short distances, i.e. in very early phase of the universe. The corresponding propagators are calculated. Tachyon matter from classical and quantum point of view is examined.