Lorentzian Robin Universe
Manishankar Ailiga, Shubhashis Mallik, Gaurav Narain

TL;DR
This paper investigates the gravitational path integral of Gauss-Bonnet gravity with Robin boundary conditions, revealing that the universe favors Hartle-Hawking initial states and transitions from Euclidean to Lorentzian signature, supported by exact and saddle point analyses.
Contribution
It computes the surface terms for Gauss-Bonnet gravity with Robin boundary conditions and performs an exact transition amplitude calculation, extending previous work to include these boundary conditions.
Findings
Gauss-Bonnet gravity favors Hartle-Hawking no-boundary initial states.
The universe transitions from Euclidean to Lorentzian signature during expansion.
Initial configurations with positive Gauss-Bonnet coupling dominate the path integral.
Abstract
In this paper, we delve into the gravitational path integral of Gauss-Bonnet gravity in four spacetime dimensions, in the mini-superspace approximation. Our primary focus lies in investigating the transition amplitude between distinct boundary configurations. Of particular interest is the case of Robin boundary conditions, known to lead to a stable Universe in Einstein-Hilbert gravity, alongside Neumann boundary conditions. To ensure a consistent variational problem, we supplement the bulk action with suitable surface terms. This study leads us to compute the necessary surface terms required for Gauss-Bonnet gravity with the Robin boundary condition, which wasn't known earlier. Thereafter, we perform an exact computation of the transition amplitude. Through analysis, we discover that the Gauss-Bonnet gravity inherently favors the initial configuration, aligning with the…
Peer Reviews
No public reviews on file for this paper yet. If you reviewed it on a platform where reviews are public (OpenReview, ICLR, NeurIPS, ICML), you can paste yours below so the community can read it here.
Videos
No videos yet. Explain this paper in a talk, walkthrough, or lecture? Add one.
Taxonomy
TopicsCosmology and Gravitation Theories · Black Holes and Theoretical Physics · Advanced Differential Geometry Research
