Lorentzian quantum cosmology
By Job Leon Feldbrugge, J. Lehners, N. Turok. 2017
220 citations recorded by the source corpus.
We argue that the Lorentzian path integral is a better starting point for quantum cosmology than its Euclidean counterpart. In particular, we revisit the minisuperspace calculation of the Feynman path integral for quantum gravity with a positive cosmological constant. Instead of rotating to Euclidean time, we deform the contour of integration over metrics into the complex plane, exploiting Picard-Lefschetz theory to transform the path integral from a conditionally convergent integral into an absolutely convergent one. We show that this procedure unambiguously determines which semiclassical saddle point solutions are relevant to the quantum mechanical amplitude. Imposing ``no-boundary'' initial conditions, i.e., restricting attention to regular, complex metrics with no initial boundary, we find that the dominant saddle contributes a semiclassical exponential factor which is precisely the inverse of the famous Hartle-Hawking result.
View Paper: https://www.semanticscholar.org/paper/f86713c5da882c1d0eff13f00affdcb6f911cfac
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Citations in the corpus
- A primer on resurgent transseries and their asymptotics (2018, background): “, [136, 51, 215, 134, 113, 114] (see [119] for further earlier references), the modern (physical) version of resurgence theory has itself recently resurged in many areas, from quantum mechanics [8–10, 242–244, 157, 7, 156, 158, 101, 27, 15, 129, 102, 187, 126, 122, 127, 221, 107, 166, 213, 65, 28, 1”
- A Note On Complex Spacetime Metrics (2021, unknown): “See [28] for a discussion of this formalism in the context of gravity (and an introduction to the formalism).”