Quantum creation of the universe is described by the {\em density matrix}
defined by the Euclidean path integral. This yields an ensemble of universes --
a cosmological landscape -- in a mixed quasi-thermal state which is shown to be
dynamically more preferable than the pure quantum state of the Hartle-Hawking
type. The latter is suppressed by the infinitely large positive action of its
instanton, generated by the conformal anomaly of quantum matter. The
Hartle-Hawking instantons can be regarded as posing initial conditions for
Starobinsky solutions of the anomaly driven deSitter expansion, which are thus
dynamically eliminated by infrared effects of quantum gravity. The resulting
landscape of hot universes treated within the cosmological bootstrap (the
self-consistent back reaction of quantum matter) turns out to be limited to a
bounded range of the cosmological constant, which rules out a well-known
infrared catastrophe of the vanishing cosmological constant and suggests an
ultimate solution to the problem of unboundedness of the cosmological action in
Euclidean quantum gravity.Comment: 6 pages, to be published in the Special issue of J. Phys. A dedicated
to the Quantum Theories and Renormalization Group in Gravity and Cosmology
(IRGAC 2006, Barcelona, Spain, 11-15 July 2006
