Quantum Kaluza-Klein cosmologies - I

Hartle and Hawking recently put forward the ground state proposal for the wave function of the universe, which incorporates the idea that the universe must come from nothing. We give two models of quantum Kaluza-Klein cosmologies in 5-dimensions. In the first model there is an isotropic cosmological constant, which eventually leads to an isotropically expanding universe. For the second model, the cosmological constant is assumed to be anisotropic, which leads to the spontaneous compactification of the fifth dimension. (author)