27 lines
748 B
Text
27 lines
748 B
Text
/-
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Copyright (c) 2024 Joseph Tooby-Smith. All rights reserved.
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Released under Apache 2.0 license as described in the file LICENSE.
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Authors: Joseph Tooby-Smith
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-/
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import HepLean.PerturbationTheory.Wick.Species
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/-!
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# Wick's theorem
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Wick's theorem is related to a result in probability theory called Isserlis' theorem.
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-/
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namespace Wick
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open CategoryTheory
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open FeynmanDiagram
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open PreFeynmanRule
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informal_lemma wicks_theorem where
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math :≈ "Wick's theorem for fields which are not normally ordered."
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informal_lemma wicks_theorem_normal_order where
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math :≈ "Wick's theorem for which fields at the same space-time point are normally ordered."
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ref :≈ "https://www.physics.purdue.edu/~clarkt/Courses/Physics662/ps/qftch32.pdf"
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end Wick
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