We propose the mechanism of quantum creation of the open Universe in the
observable range of values of Ω. This mechanism is based on the
no-boundary quantum state with the Hawking-Turok instanton applied to the model
with a strong nonminimal coupling of the inflaton field. We develop the slow
roll perturbation expansion for the instanton solution and obtain a nontrivial
contribution to the classical instanton action. The interplay of this classical
contribution with the loop effects due to quantum effective action generates
the probability distribution peak with necessary parameters of the inflation
stage without invoking any anthropic considerations. In contrast with a similar
mechanism for closed models, existing only for the tunneling quantum state of
the Universe, the observationally justified open inflation originates from the
no-boundary cosmological wavefunction.Comment: 28 pages, LaTe