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arXiv · 2104.02816

An index theorem on asymptotically static spacetimes with compact Cauchy surface

Dawei Shen·Michał Wrochna
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Abstract

We consider the Dirac operator on asymptotically static Lorentzian manifolds with an odd-dimensional compact Cauchy surface. We prove that if Atiyah-Patodi-Singer boundary conditions are imposed at infinite times then the Dirac operator is Fredholm. This generalizes a theorem due to Bär-Strohmaier in the case of finite times, and we also show that the corresponding index formula extends to the infinite setting. Furthermore, we demonstrate the existence of a Fredholm inverse which is at the same time a Feynman parametrix in the sense of Duistermaat-Hörmander. The proof combines methods from time-dependent scattering theory with a variant of Egorov's theorem for pseudo-differential hyperbolic systems.

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Dawei Shen, Michał Wrochna. 2022-03-24. An index theorem on asymptotically static spacetimes with compact Cauchy surface. https://doi.org/10.2140/paa.2022.4.727

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