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High Energy Physics - Theory, hep-th,General Relativity and Quantum Cosmology, gr-qc
Abstract:
We study the emergence of anisotropic (Bianchi IX) inflationary universes
with no-boundary conditions in the path integral approach to quantum gravity.
In contrast to previous work, we find no evidence for any limit to how large
the anisotropies can become, although for increasing anisotropies the shape of
the instantons becomes significantly different from Hawking's original
no-boundary instanton. In all cases an inflationary phase is reached, with the
anisotropies decaying away. Larger anisotropies are associated with a much
larger imaginary part of the action, implying that the highly anisotropic
branches of the wavefunction are heavily suppressed. Interestingly, the
presence of anisotropies causes the wavefunction to become classical much more
slowly than for isotropic inflationary universes. We derive the associated
scaling of the WKB classicality conditions both numerically and analytically.
