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GR: Fachverband Gravitation und Relativitätstheorie

GR 10: Scalar-tensor and non-local gravity theories

GR 10.2: Vortrag

Donnerstag, 2. September 2021, 17:45–18:00, H9

Topological defects and regularity in non-local gravity — •Jens Boos — William & Mary, Williamsburg, United States

Non-local gravitational theories with infinitely many derivatives may solve the gravitational singularity problem without introducing ghost-like degrees of freedom that one typically encounters in higher-order gravity. However, due to the complexity of the non-linear non-local field equations, so far only the linear regime is understood well. In this talk I will focus on cosmic string solutions obtained in weak-field non-local gravity. These have an interesting feature: non-locality regularizes the curvature defect at the location of the cosmic string. Since spacetime is now simply connected one might assume that the angle deficit vanishes, but this is not true: asymptotically one recovers the string solution of General Relativity. Non-locality hence challenges the way we think about topological defects in connection with topological properties of spacetime. If time permits, I shall also comment on similar effects regarding Aharanov--Bohm phases in non-local quantum mechanics, and their possible observational signatures.