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High Energy Theory artwork
April 25, 20222:00 pm – 3:00 pm (CDT)

Complex Saddles and Euclidean Wormholes in the Lorentzian Path Integral


Gary Shiu (University of Wisconsin-Madison)


Ergin Sezgin



Mitchell Institute for Fundamental Physics & Astronomy

College Station, Texas 77843

Event Details

We study complex saddles of the Lorentzian path integral for 4D axion gravity and its dual description in terms of a 3-form flux, which include the Giddings-Strominger Euclidean wormhole. Transition amplitudes are computed using the Lorentzian path integral and with the help of Picard-Lefschetz theory. The number and nature of saddles is shown to qualitatively change in the presence of a bilocal operator that could arise, for example, as a result of considering higher-topology transitions. We also analyze the stability of the Giddings-Strominger wormhole in the 3-form picture, where we find that it represents a perturbatively stable Euclidean saddle of the gravitational path integral. This calls into question the ultimate fate of such solutions in an ultraviolet-complete theory of quantum gravity.

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