Real no-boundary wave function in Lorentzian quantum cosmology

© 2017 American Physical Society. It is shown that the standard no-boundary wave function has a natural expression in terms of a Lorentzian path integral with its contour defined by Picard-Lefschetz theory. The wave function is real, satisfies the Wheeler-DeWitt equation and predicts an ensemble of asymptotically classical, inflationary universes with nearly-Gaussian fluctuations and with a smooth semiclassical origin.1 + 10.5 + 2.5 pages, 2 figures. v2: minor changes and added referencesstatus: publishe