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Fermionic alpha-vacua

Hael Collins
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Abstract

A spin one-half particle propagating in a de Sitter background has a one parameter family of states which transform covariantly under the isometry group of the background. These states are the fermionic analogues of the alpha-vacua for a scalar field. We shall show how using a point-source propagator for a fermion in an alpha-state produces divergent perturbative corrections. These corrections cannot be used to cancel similar divergences arising from scalar fields in bosonic alpha-vacua since they have an incompatible dependence on the external momenta. The theory can be regularized by modifying the propagator to include an antipodal source.

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Hael Collins. 2004-10-22. Fermionic alpha-vacua. https://doi.org/10.1103/physrevd.71.024002

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