High Energy Theory Seminar

In this talk (based on https://arxiv.org/abs/2504.00920) I will discuss the phase of the Euclidean path integral in pure gravity with a positive cosmological constant, and its relation to physical instabilities of the associated saddles. I will first illustrate the idea by discussing the phase of the Euclidean path integral for simple unstable systems. I will then discuss the phase of the sphere partition function and use gauge invariance to argue for the correct choice of the contour of integration. 

Having this setup, I will calculate the phase of the path integral for a class of saddle geometries and show a quantitative relation between the phase of the path integral in $S^p x M_q$, and a "number of physical negative modes" in dS_p x M_q, with M any Einstein manifold.

The talk is in 469 Lauritsen.

Contact [email protected] for Zoom information.