On microlocalisation and the construction of Feynman Propagators for normally hyperbolic operators

Fuente: arXiv
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Hauptverfasser: Islam, Onirban, Strohmaier, Alexander
Format: Preprint
Veröffentlicht: 2020
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author Islam, Onirban
Strohmaier, Alexander
author_facet Islam, Onirban
Strohmaier, Alexander
contents This article gives global microlocalisation constructions for normally hyperbolic operators on a vector bundle over a globally hyperbolic spacetime in geometric terms. As an application, this is used to generalise the Duistermaat-Hörmander construction of Feynman propagators, therefore incorporating the most important non-scalar geometric operators. It is shown that for normally hyperbolic operators that are selfadjoint with respect to a hermitian bundle metric, the Feynman propagators can be constructed to satisfy a positivity property that reflects the existence of Hadamard states in quantum field theory on curved spacetimes. We also give a more direct construction of the Feynman propagators for Dirac-type operators on a globally hyperbolic spacetime. Even though the natural bundle metric on spinors is not positive-definite, in this case, we can give a direct microlocal construction of a Feynman propagator that satisfies positivity.
format Preprint
id arxiv_https___arxiv_org_abs_2012_09767
institution arXiv
publishDate 2020
record_format arxiv
spellingShingle On microlocalisation and the construction of Feynman Propagators for normally hyperbolic operators
Islam, Onirban
Strohmaier, Alexander
Analysis of PDEs
Mathematical Physics
Differential Geometry
35S30, 58J40, 81T20
This article gives global microlocalisation constructions for normally hyperbolic operators on a vector bundle over a globally hyperbolic spacetime in geometric terms. As an application, this is used to generalise the Duistermaat-Hörmander construction of Feynman propagators, therefore incorporating the most important non-scalar geometric operators. It is shown that for normally hyperbolic operators that are selfadjoint with respect to a hermitian bundle metric, the Feynman propagators can be constructed to satisfy a positivity property that reflects the existence of Hadamard states in quantum field theory on curved spacetimes. We also give a more direct construction of the Feynman propagators for Dirac-type operators on a globally hyperbolic spacetime. Even though the natural bundle metric on spinors is not positive-definite, in this case, we can give a direct microlocal construction of a Feynman propagator that satisfies positivity.
title On microlocalisation and the construction of Feynman Propagators for normally hyperbolic operators
topic Analysis of PDEs
Mathematical Physics
Differential Geometry
35S30, 58J40, 81T20
url https://arxiv.org/abs/2012.09767