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arXiv · 2002.09448

Hadamard parametrix of the Feynman Green's function of a five-dimensional charged scalar field

Visakan Balakumar·Elizabeth Winstanley
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Abstract

The Hadamard parametrix is a representation of the short-distance singularity structure of the Feynman Green's function for a quantum field on a curved space-time background. Subtracting these divergent terms regularizes the Feynman Green's function and enables the computation of renormalized expectation values of observables. We study the Hadamard parametrix for a charged, massive, complex scalar field in five space-time dimensions. Even in Minkowski space-time, it is not possible to write the Feynman Green's function for a charged scalar field exactly in closed form. We therefore present covariant Taylor series expansions for the biscalars arising in the Hadamard parametrix. On a general space-time background, we explicitly state the expansion coefficients up to the order required for the computation of the renormalized scalar field current. These coefficients become increasingly lengthy as the order of the expansion increases, so we give the higher-order terms required for the calculation of the renormalized stress-energy tensor in Minkowski space-time only.

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Visakan Balakumar, Elizabeth Winstanley. 2020-02-21. Hadamard parametrix of the Feynman Green's function of a five-dimensional charged scalar field. https://arxiv.org/abs/2002.09448

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