feat: Add Wick terms

This commit is contained in:
jstoobysmith 2025-02-05 08:52:14 +00:00
parent 7d9e6af80c
commit 2e82f842a2
12 changed files with 634 additions and 553 deletions

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@ -128,11 +128,14 @@ import HepLean.PerturbationTheory.FeynmanDiagrams.Instances.Phi4
import HepLean.PerturbationTheory.FeynmanDiagrams.Momentum
import HepLean.PerturbationTheory.FieldOpAlgebra.Basic
import HepLean.PerturbationTheory.FieldOpAlgebra.Grading
import HepLean.PerturbationTheory.FieldOpAlgebra.NormalOrder
import HepLean.PerturbationTheory.FieldOpAlgebra.NormalOrder.Basic
import HepLean.PerturbationTheory.FieldOpAlgebra.NormalOrder.Lemmas
import HepLean.PerturbationTheory.FieldOpAlgebra.NormalOrder.WickContractions
import HepLean.PerturbationTheory.FieldOpAlgebra.StaticWickTheorem
import HepLean.PerturbationTheory.FieldOpAlgebra.SuperCommute
import HepLean.PerturbationTheory.FieldOpAlgebra.TimeContraction
import HepLean.PerturbationTheory.FieldOpAlgebra.TimeOrder
import HepLean.PerturbationTheory.FieldOpAlgebra.WickTerm
import HepLean.PerturbationTheory.FieldOpAlgebra.WicksTheorem
import HepLean.PerturbationTheory.FieldOpAlgebra.WicksTheoremNormal
import HepLean.PerturbationTheory.FieldOpFreeAlgebra.Basic

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@ -0,0 +1,240 @@
/-
Copyright (c) 2025 Joseph Tooby-Smith. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.
Authors: Joseph Tooby-Smith
-/
import HepLean.PerturbationTheory.FieldOpFreeAlgebra.NormalOrder
import HepLean.PerturbationTheory.FieldOpAlgebra.SuperCommute
/-!
# Normal Ordering on Field operator algebra
-/
namespace FieldSpecification
open FieldOpFreeAlgebra
open HepLean.List
open FieldStatistic
namespace FieldOpAlgebra
variable {𝓕 : FieldSpecification}
/-!
## Normal order on super-commutators.
The main result of this is
`ι_normalOrderF_superCommuteF_eq_zero_mul`
which states that applying `ι` to the normal order of something containing a super-commutator
is zero.
-/
lemma ι_normalOrderF_superCommuteF_ofCrAnListF_ofCrAnListF_eq_zero
(φa φa' : 𝓕.CrAnFieldOp) (φs φs' : List 𝓕.CrAnFieldOp) :
ι 𝓝ᶠ(ofCrAnListF φs * [ofCrAnOpF φa, ofCrAnOpF φa']ₛca * ofCrAnListF φs') = 0 := by
rcases CreateAnnihilate.eq_create_or_annihilate (𝓕 |>ᶜ φa) with hφa | hφa
<;> rcases CreateAnnihilate.eq_create_or_annihilate (𝓕 |>ᶜ φa') with hφa' | hφa'
· rw [normalOrderF_superCommuteF_ofCrAnListF_create_create_ofCrAnListF φa φa' hφa hφa' φs φs']
rw [map_smul, map_mul, map_mul, map_mul, ι_superCommuteF_of_create_create φa φa' hφa hφa']
simp
· rw [normalOrderF_superCommuteF_create_annihilate φa φa' hφa hφa' (ofCrAnListF φs)
(ofCrAnListF φs')]
simp
· rw [normalOrderF_superCommuteF_annihilate_create φa' φa hφa' hφa (ofCrAnListF φs)
(ofCrAnListF φs')]
simp
· rw [normalOrderF_superCommuteF_ofCrAnListF_annihilate_annihilate_ofCrAnListF
φa φa' hφa hφa' φs φs']
rw [map_smul, map_mul, map_mul, map_mul,
ι_superCommuteF_of_annihilate_annihilate φa φa' hφa hφa']
simp
lemma ι_normalOrderF_superCommuteF_ofCrAnListF_eq_zero
(φa φa' : 𝓕.CrAnFieldOp) (φs : List 𝓕.CrAnFieldOp)
(a : 𝓕.FieldOpFreeAlgebra) :
ι 𝓝ᶠ(ofCrAnListF φs * [ofCrAnOpF φa, ofCrAnOpF φa']ₛca * a) = 0 := by
have hf : ι.toLinearMap ∘ₗ normalOrderF ∘ₗ
mulLinearMap (ofCrAnListF φs * [ofCrAnOpF φa, ofCrAnOpF φa']ₛca) = 0 := by
apply ofCrAnListFBasis.ext
intro l
simp only [FieldOpFreeAlgebra.ofListBasis_eq_ofList, LinearMap.coe_comp, Function.comp_apply,
AlgHom.toLinearMap_apply, LinearMap.zero_apply]
exact ι_normalOrderF_superCommuteF_ofCrAnListF_ofCrAnListF_eq_zero φa φa' φs l
change (ι.toLinearMap ∘ₗ normalOrderF ∘ₗ
mulLinearMap ((ofCrAnListF φs * [ofCrAnOpF φa, ofCrAnOpF φa']ₛca))) a = 0
rw [hf]
simp
lemma ι_normalOrderF_superCommuteF_ofCrAnOpF_eq_zero_mul (φa φa' : 𝓕.CrAnFieldOp)
(a b : 𝓕.FieldOpFreeAlgebra) :
ι 𝓝ᶠ(a * [ofCrAnOpF φa, ofCrAnOpF φa']ₛca * b) = 0 := by
rw [mul_assoc]
change (ι.toLinearMap ∘ₗ normalOrderF ∘ₗ mulLinearMap.flip
([ofCrAnOpF φa, ofCrAnOpF φa']ₛca * b)) a = 0
have hf : ι.toLinearMap ∘ₗ normalOrderF ∘ₗ mulLinearMap.flip
([ofCrAnOpF φa, ofCrAnOpF φa']ₛca * b) = 0 := by
apply ofCrAnListFBasis.ext
intro l
simp only [mulLinearMap, FieldOpFreeAlgebra.ofListBasis_eq_ofList, LinearMap.coe_comp,
Function.comp_apply, LinearMap.flip_apply, LinearMap.coe_mk, AddHom.coe_mk,
AlgHom.toLinearMap_apply, LinearMap.zero_apply]
rw [← mul_assoc]
exact ι_normalOrderF_superCommuteF_ofCrAnListF_eq_zero φa φa' _ _
rw [hf]
simp
lemma ι_normalOrderF_superCommuteF_ofCrAnOpF_ofCrAnListF_eq_zero_mul (φa : 𝓕.CrAnFieldOp)
(φs : List 𝓕.CrAnFieldOp) (a b : 𝓕.FieldOpFreeAlgebra) :
ι 𝓝ᶠ(a * [ofCrAnOpF φa, ofCrAnListF φs]ₛca * b) = 0 := by
rw [← ofCrAnListF_singleton, superCommuteF_ofCrAnListF_ofCrAnListF_eq_sum]
rw [Finset.mul_sum, Finset.sum_mul]
rw [map_sum, map_sum]
apply Fintype.sum_eq_zero
intro n
rw [← mul_assoc, ← mul_assoc]
rw [mul_assoc _ _ b, ofCrAnListF_singleton]
rw [ι_normalOrderF_superCommuteF_ofCrAnOpF_eq_zero_mul]
lemma ι_normalOrderF_superCommuteF_ofCrAnListF_ofCrAnOpF_eq_zero_mul (φa : 𝓕.CrAnFieldOp)
(φs : List 𝓕.CrAnFieldOp) (a b : 𝓕.FieldOpFreeAlgebra) :
ι 𝓝ᶠ(a * [ofCrAnListF φs, ofCrAnOpF φa]ₛca * b) = 0 := by
rw [← ofCrAnListF_singleton, superCommuteF_ofCrAnListF_ofCrAnListF_symm, ofCrAnListF_singleton]
simp only [FieldStatistic.instCommGroup.eq_1, FieldStatistic.ofList_singleton, mul_neg,
Algebra.mul_smul_comm, neg_mul, Algebra.smul_mul_assoc, map_neg, map_smul]
rw [ι_normalOrderF_superCommuteF_ofCrAnOpF_ofCrAnListF_eq_zero_mul]
simp
lemma ι_normalOrderF_superCommuteF_ofCrAnListF_ofCrAnListF_eq_zero_mul
(φs φs' : List 𝓕.CrAnFieldOp) (a b : 𝓕.FieldOpFreeAlgebra) :
ι 𝓝ᶠ(a * [ofCrAnListF φs, ofCrAnListF φs']ₛca * b) = 0 := by
rw [superCommuteF_ofCrAnListF_ofCrAnListF_eq_sum, Finset.mul_sum, Finset.sum_mul]
rw [map_sum, map_sum]
apply Fintype.sum_eq_zero
intro n
rw [← mul_assoc, ← mul_assoc]
rw [mul_assoc _ _ b]
rw [ι_normalOrderF_superCommuteF_ofCrAnListF_ofCrAnOpF_eq_zero_mul]
lemma ι_normalOrderF_superCommuteF_ofCrAnListF_eq_zero_mul
(φs : List 𝓕.CrAnFieldOp)
(a b c : 𝓕.FieldOpFreeAlgebra) :
ι 𝓝ᶠ(a * [ofCrAnListF φs, c]ₛca * b) = 0 := by
change (ι.toLinearMap ∘ₗ normalOrderF ∘ₗ
mulLinearMap.flip b ∘ₗ mulLinearMap a ∘ₗ superCommuteF (ofCrAnListF φs)) c = 0
have hf : (ι.toLinearMap ∘ₗ normalOrderF ∘ₗ
mulLinearMap.flip b ∘ₗ mulLinearMap a ∘ₗ superCommuteF (ofCrAnListF φs)) = 0 := by
apply ofCrAnListFBasis.ext
intro φs'
simp only [mulLinearMap, LinearMap.coe_mk, AddHom.coe_mk, ofListBasis_eq_ofList,
LinearMap.coe_comp, Function.comp_apply, LinearMap.flip_apply, AlgHom.toLinearMap_apply,
LinearMap.zero_apply]
rw [ι_normalOrderF_superCommuteF_ofCrAnListF_ofCrAnListF_eq_zero_mul]
rw [hf]
simp
@[simp]
lemma ι_normalOrderF_superCommuteF_eq_zero_mul
(a b c d : 𝓕.FieldOpFreeAlgebra) : ι 𝓝ᶠ(a * [d, c]ₛca * b) = 0 := by
change (ι.toLinearMap ∘ₗ normalOrderF ∘ₗ
mulLinearMap.flip b ∘ₗ mulLinearMap a ∘ₗ superCommuteF.flip c) d = 0
have hf : (ι.toLinearMap ∘ₗ normalOrderF ∘ₗ
mulLinearMap.flip b ∘ₗ mulLinearMap a ∘ₗ superCommuteF.flip c) = 0 := by
apply ofCrAnListFBasis.ext
intro φs
simp only [mulLinearMap, LinearMap.coe_mk, AddHom.coe_mk, ofListBasis_eq_ofList,
LinearMap.coe_comp, Function.comp_apply, LinearMap.flip_apply, AlgHom.toLinearMap_apply,
LinearMap.zero_apply]
rw [ι_normalOrderF_superCommuteF_ofCrAnListF_eq_zero_mul]
rw [hf]
simp
@[simp]
lemma ι_normalOrder_superCommuteF_eq_zero_mul_right (b c d : 𝓕.FieldOpFreeAlgebra) :
ι 𝓝ᶠ([d, c]ₛca * b) = 0 := by
rw [← ι_normalOrderF_superCommuteF_eq_zero_mul 1 b c d]
simp
@[simp]
lemma ι_normalOrderF_superCommuteF_eq_zero_mul_left (a c d : 𝓕.FieldOpFreeAlgebra) :
ι 𝓝ᶠ(a * [d, c]ₛca) = 0 := by
rw [← ι_normalOrderF_superCommuteF_eq_zero_mul a 1 c d]
simp
@[simp]
lemma ι_normalOrderF_superCommuteF_eq_zero_mul_mul_right (a b1 b2 c d: 𝓕.FieldOpFreeAlgebra) :
ι 𝓝ᶠ(a * [d, c]ₛca * b1 * b2) = 0 := by
rw [← ι_normalOrderF_superCommuteF_eq_zero_mul a (b1 * b2) c d]
congr 2
noncomm_ring
@[simp]
lemma ι_normalOrderF_superCommuteF_eq_zero (c d : 𝓕.FieldOpFreeAlgebra) : ι 𝓝ᶠ([d, c]ₛca) = 0 := by
rw [← ι_normalOrderF_superCommuteF_eq_zero_mul 1 1 c d]
simp
/-!
## Defining normal order for `FiedOpAlgebra`.
-/
lemma ι_normalOrderF_zero_of_mem_ideal (a : 𝓕.FieldOpFreeAlgebra)
(h : a ∈ TwoSidedIdeal.span 𝓕.fieldOpIdealSet) : ι 𝓝ᶠ(a) = 0 := by
rw [TwoSidedIdeal.mem_span_iff_mem_addSubgroup_closure] at h
let p {k : Set 𝓕.FieldOpFreeAlgebra} (a : FieldOpFreeAlgebra 𝓕)
(h : a ∈ AddSubgroup.closure k) := ι 𝓝ᶠ(a) = 0
change p a h
apply AddSubgroup.closure_induction
· intro x hx
obtain ⟨a, ha, b, hb, rfl⟩ := Set.mem_mul.mp hx
obtain ⟨a, ha, c, hc, rfl⟩ := ha
simp only [p]
simp only [fieldOpIdealSet, exists_prop, exists_and_left, Set.mem_setOf_eq] at hc
match hc with
| Or.inl hc =>
obtain ⟨φa, φa', hφa, hφa', rfl⟩ := hc
simp [mul_sub, sub_mul, ← mul_assoc]
| Or.inr (Or.inl hc) =>
obtain ⟨φa, φa', hφa, hφa', rfl⟩ := hc
simp [mul_sub, sub_mul, ← mul_assoc]
| Or.inr (Or.inr (Or.inl hc)) =>
obtain ⟨φa, φa', hφa, hφa', rfl⟩ := hc
simp [mul_sub, sub_mul, ← mul_assoc]
| Or.inr (Or.inr (Or.inr hc)) =>
obtain ⟨φa, φa', hφa, hφa', rfl⟩ := hc
simp [mul_sub, sub_mul, ← mul_assoc]
· simp [p]
· intro x y hx hy
simp only [map_add, p]
intro h1 h2
simp [h1, h2]
· intro x hx
simp [p]
lemma ι_normalOrderF_eq_of_equiv (a b : 𝓕.FieldOpFreeAlgebra) (h : a ≈ b) :
ι 𝓝ᶠ(a) = ι 𝓝ᶠ(b) := by
rw [equiv_iff_sub_mem_ideal] at h
rw [LinearMap.sub_mem_ker_iff.mp]
simp only [LinearMap.mem_ker, ← map_sub]
exact ι_normalOrderF_zero_of_mem_ideal (a - b) h
/-- Normal ordering on `FieldOpAlgebra`. -/
noncomputable def normalOrder : FieldOpAlgebra 𝓕 →ₗ[] FieldOpAlgebra 𝓕 where
toFun := Quotient.lift (ι.toLinearMap ∘ₗ normalOrderF) ι_normalOrderF_eq_of_equiv
map_add' x y := by
obtain ⟨x, rfl⟩ := ι_surjective x
obtain ⟨y, rfl⟩ := ι_surjective y
rw [← map_add, ι_apply, ι_apply, ι_apply]
rw [Quotient.lift_mk, Quotient.lift_mk, Quotient.lift_mk]
simp
map_smul' c y := by
obtain ⟨y, rfl⟩ := ι_surjective y
rw [← map_smul, ι_apply, ι_apply]
simp
@[inherit_doc normalOrder]
scoped[FieldSpecification.FieldOpAlgebra] notation "𝓝(" a ")" => normalOrder a
end FieldOpAlgebra
end FieldSpecification

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@ -3,11 +3,10 @@ Copyright (c) 2025 Joseph Tooby-Smith. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.
Authors: Joseph Tooby-Smith
-/
import HepLean.PerturbationTheory.FieldOpFreeAlgebra.NormalOrder
import HepLean.PerturbationTheory.FieldOpAlgebra.SuperCommute
import HepLean.PerturbationTheory.FieldOpAlgebra.NormalOrder.Basic
/-!
# Normal Ordering on Field operator algebra
# Basic properties of normal ordering
-/
@ -21,224 +20,6 @@ variable {𝓕 : FieldSpecification}
/-!
## Normal order on super-commutators.
The main result of this is
`ι_normalOrderF_superCommuteF_eq_zero_mul`
which states that applying `ι` to the normal order of something containing a super-commutator
is zero.
-/
lemma ι_normalOrderF_superCommuteF_ofCrAnListF_ofCrAnListF_eq_zero
(φa φa' : 𝓕.CrAnFieldOp) (φs φs' : List 𝓕.CrAnFieldOp) :
ι 𝓝ᶠ(ofCrAnListF φs * [ofCrAnOpF φa, ofCrAnOpF φa']ₛca * ofCrAnListF φs') = 0 := by
rcases CreateAnnihilate.eq_create_or_annihilate (𝓕 |>ᶜ φa) with hφa | hφa
<;> rcases CreateAnnihilate.eq_create_or_annihilate (𝓕 |>ᶜ φa') with hφa' | hφa'
· rw [normalOrderF_superCommuteF_ofCrAnListF_create_create_ofCrAnListF φa φa' hφa hφa' φs φs']
rw [map_smul, map_mul, map_mul, map_mul, ι_superCommuteF_of_create_create φa φa' hφa hφa']
simp
· rw [normalOrderF_superCommuteF_create_annihilate φa φa' hφa hφa' (ofCrAnListF φs)
(ofCrAnListF φs')]
simp
· rw [normalOrderF_superCommuteF_annihilate_create φa' φa hφa' hφa (ofCrAnListF φs)
(ofCrAnListF φs')]
simp
· rw [normalOrderF_superCommuteF_ofCrAnListF_annihilate_annihilate_ofCrAnListF
φa φa' hφa hφa' φs φs']
rw [map_smul, map_mul, map_mul, map_mul,
ι_superCommuteF_of_annihilate_annihilate φa φa' hφa hφa']
simp
lemma ι_normalOrderF_superCommuteF_ofCrAnListF_eq_zero
(φa φa' : 𝓕.CrAnFieldOp) (φs : List 𝓕.CrAnFieldOp)
(a : 𝓕.FieldOpFreeAlgebra) :
ι 𝓝ᶠ(ofCrAnListF φs * [ofCrAnOpF φa, ofCrAnOpF φa']ₛca * a) = 0 := by
have hf : ι.toLinearMap ∘ₗ normalOrderF ∘ₗ
mulLinearMap (ofCrAnListF φs * [ofCrAnOpF φa, ofCrAnOpF φa']ₛca) = 0 := by
apply ofCrAnListFBasis.ext
intro l
simp only [FieldOpFreeAlgebra.ofListBasis_eq_ofList, LinearMap.coe_comp, Function.comp_apply,
AlgHom.toLinearMap_apply, LinearMap.zero_apply]
exact ι_normalOrderF_superCommuteF_ofCrAnListF_ofCrAnListF_eq_zero φa φa' φs l
change (ι.toLinearMap ∘ₗ normalOrderF ∘ₗ
mulLinearMap ((ofCrAnListF φs * [ofCrAnOpF φa, ofCrAnOpF φa']ₛca))) a = 0
rw [hf]
simp
lemma ι_normalOrderF_superCommuteF_ofCrAnOpF_eq_zero_mul (φa φa' : 𝓕.CrAnFieldOp)
(a b : 𝓕.FieldOpFreeAlgebra) :
ι 𝓝ᶠ(a * [ofCrAnOpF φa, ofCrAnOpF φa']ₛca * b) = 0 := by
rw [mul_assoc]
change (ι.toLinearMap ∘ₗ normalOrderF ∘ₗ mulLinearMap.flip
([ofCrAnOpF φa, ofCrAnOpF φa']ₛca * b)) a = 0
have hf : ι.toLinearMap ∘ₗ normalOrderF ∘ₗ mulLinearMap.flip
([ofCrAnOpF φa, ofCrAnOpF φa']ₛca * b) = 0 := by
apply ofCrAnListFBasis.ext
intro l
simp only [mulLinearMap, FieldOpFreeAlgebra.ofListBasis_eq_ofList, LinearMap.coe_comp,
Function.comp_apply, LinearMap.flip_apply, LinearMap.coe_mk, AddHom.coe_mk,
AlgHom.toLinearMap_apply, LinearMap.zero_apply]
rw [← mul_assoc]
exact ι_normalOrderF_superCommuteF_ofCrAnListF_eq_zero φa φa' _ _
rw [hf]
simp
lemma ι_normalOrderF_superCommuteF_ofCrAnOpF_ofCrAnListF_eq_zero_mul (φa : 𝓕.CrAnFieldOp)
(φs : List 𝓕.CrAnFieldOp)
(a b : 𝓕.FieldOpFreeAlgebra) :
ι 𝓝ᶠ(a * [ofCrAnOpF φa, ofCrAnListF φs]ₛca * b) = 0 := by
rw [← ofCrAnListF_singleton, superCommuteF_ofCrAnListF_ofCrAnListF_eq_sum]
rw [Finset.mul_sum, Finset.sum_mul]
rw [map_sum, map_sum]
apply Fintype.sum_eq_zero
intro n
rw [← mul_assoc, ← mul_assoc]
rw [mul_assoc _ _ b, ofCrAnListF_singleton]
rw [ι_normalOrderF_superCommuteF_ofCrAnOpF_eq_zero_mul]
lemma ι_normalOrderF_superCommuteF_ofCrAnListF_ofCrAnOpF_eq_zero_mul (φa : 𝓕.CrAnFieldOp)
(φs : List 𝓕.CrAnFieldOp) (a b : 𝓕.FieldOpFreeAlgebra) :
ι 𝓝ᶠ(a * [ofCrAnListF φs, ofCrAnOpF φa]ₛca * b) = 0 := by
rw [← ofCrAnListF_singleton, superCommuteF_ofCrAnListF_ofCrAnListF_symm, ofCrAnListF_singleton]
simp only [FieldStatistic.instCommGroup.eq_1, FieldStatistic.ofList_singleton, mul_neg,
Algebra.mul_smul_comm, neg_mul, Algebra.smul_mul_assoc, map_neg, map_smul]
rw [ι_normalOrderF_superCommuteF_ofCrAnOpF_ofCrAnListF_eq_zero_mul]
simp
lemma ι_normalOrderF_superCommuteF_ofCrAnListF_ofCrAnListF_eq_zero_mul
(φs φs' : List 𝓕.CrAnFieldOp) (a b : 𝓕.FieldOpFreeAlgebra) :
ι 𝓝ᶠ(a * [ofCrAnListF φs, ofCrAnListF φs']ₛca * b) = 0 := by
rw [superCommuteF_ofCrAnListF_ofCrAnListF_eq_sum, Finset.mul_sum, Finset.sum_mul]
rw [map_sum, map_sum]
apply Fintype.sum_eq_zero
intro n
rw [← mul_assoc, ← mul_assoc]
rw [mul_assoc _ _ b]
rw [ι_normalOrderF_superCommuteF_ofCrAnListF_ofCrAnOpF_eq_zero_mul]
lemma ι_normalOrderF_superCommuteF_ofCrAnListF_eq_zero_mul
(φs : List 𝓕.CrAnFieldOp)
(a b c : 𝓕.FieldOpFreeAlgebra) :
ι 𝓝ᶠ(a * [ofCrAnListF φs, c]ₛca * b) = 0 := by
change (ι.toLinearMap ∘ₗ normalOrderF ∘ₗ
mulLinearMap.flip b ∘ₗ mulLinearMap a ∘ₗ superCommuteF (ofCrAnListF φs)) c = 0
have hf : (ι.toLinearMap ∘ₗ normalOrderF ∘ₗ
mulLinearMap.flip b ∘ₗ mulLinearMap a ∘ₗ superCommuteF (ofCrAnListF φs)) = 0 := by
apply ofCrAnListFBasis.ext
intro φs'
simp only [mulLinearMap, LinearMap.coe_mk, AddHom.coe_mk, ofListBasis_eq_ofList,
LinearMap.coe_comp, Function.comp_apply, LinearMap.flip_apply, AlgHom.toLinearMap_apply,
LinearMap.zero_apply]
rw [ι_normalOrderF_superCommuteF_ofCrAnListF_ofCrAnListF_eq_zero_mul]
rw [hf]
simp
@[simp]
lemma ι_normalOrderF_superCommuteF_eq_zero_mul
(a b c d : 𝓕.FieldOpFreeAlgebra) : ι 𝓝ᶠ(a * [d, c]ₛca * b) = 0 := by
change (ι.toLinearMap ∘ₗ normalOrderF ∘ₗ
mulLinearMap.flip b ∘ₗ mulLinearMap a ∘ₗ superCommuteF.flip c) d = 0
have hf : (ι.toLinearMap ∘ₗ normalOrderF ∘ₗ
mulLinearMap.flip b ∘ₗ mulLinearMap a ∘ₗ superCommuteF.flip c) = 0 := by
apply ofCrAnListFBasis.ext
intro φs
simp only [mulLinearMap, LinearMap.coe_mk, AddHom.coe_mk, ofListBasis_eq_ofList,
LinearMap.coe_comp, Function.comp_apply, LinearMap.flip_apply, AlgHom.toLinearMap_apply,
LinearMap.zero_apply]
rw [ι_normalOrderF_superCommuteF_ofCrAnListF_eq_zero_mul]
rw [hf]
simp
@[simp]
lemma ι_normalOrder_superCommuteF_eq_zero_mul_right (b c d : 𝓕.FieldOpFreeAlgebra) :
ι 𝓝ᶠ([d, c]ₛca * b) = 0 := by
rw [← ι_normalOrderF_superCommuteF_eq_zero_mul 1 b c d]
simp
@[simp]
lemma ι_normalOrderF_superCommuteF_eq_zero_mul_left (a c d : 𝓕.FieldOpFreeAlgebra) :
ι 𝓝ᶠ(a * [d, c]ₛca) = 0 := by
rw [← ι_normalOrderF_superCommuteF_eq_zero_mul a 1 c d]
simp
@[simp]
lemma ι_normalOrderF_superCommuteF_eq_zero_mul_mul_right (a b1 b2 c d: 𝓕.FieldOpFreeAlgebra) :
ι 𝓝ᶠ(a * [d, c]ₛca * b1 * b2) = 0 := by
rw [← ι_normalOrderF_superCommuteF_eq_zero_mul a (b1 * b2) c d]
congr 2
noncomm_ring
@[simp]
lemma ι_normalOrderF_superCommuteF_eq_zero (c d : 𝓕.FieldOpFreeAlgebra) : ι 𝓝ᶠ([d, c]ₛca) = 0 := by
rw [← ι_normalOrderF_superCommuteF_eq_zero_mul 1 1 c d]
simp
/-!
## Defining normal order for `FiedOpAlgebra`.
-/
lemma ι_normalOrderF_zero_of_mem_ideal (a : 𝓕.FieldOpFreeAlgebra)
(h : a ∈ TwoSidedIdeal.span 𝓕.fieldOpIdealSet) : ι 𝓝ᶠ(a) = 0 := by
rw [TwoSidedIdeal.mem_span_iff_mem_addSubgroup_closure] at h
let p {k : Set 𝓕.FieldOpFreeAlgebra} (a : FieldOpFreeAlgebra 𝓕)
(h : a ∈ AddSubgroup.closure k) := ι 𝓝ᶠ(a) = 0
change p a h
apply AddSubgroup.closure_induction
· intro x hx
obtain ⟨a, ha, b, hb, rfl⟩ := Set.mem_mul.mp hx
obtain ⟨a, ha, c, hc, rfl⟩ := ha
simp only [p]
simp only [fieldOpIdealSet, exists_prop, exists_and_left, Set.mem_setOf_eq] at hc
match hc with
| Or.inl hc =>
obtain ⟨φa, φa', hφa, hφa', rfl⟩ := hc
simp [mul_sub, sub_mul, ← mul_assoc]
| Or.inr (Or.inl hc) =>
obtain ⟨φa, φa', hφa, hφa', rfl⟩ := hc
simp [mul_sub, sub_mul, ← mul_assoc]
| Or.inr (Or.inr (Or.inl hc)) =>
obtain ⟨φa, φa', hφa, hφa', rfl⟩ := hc
simp [mul_sub, sub_mul, ← mul_assoc]
| Or.inr (Or.inr (Or.inr hc)) =>
obtain ⟨φa, φa', hφa, hφa', rfl⟩ := hc
simp [mul_sub, sub_mul, ← mul_assoc]
· simp [p]
· intro x y hx hy
simp only [map_add, p]
intro h1 h2
simp [h1, h2]
· intro x hx
simp [p]
lemma ι_normalOrderF_eq_of_equiv (a b : 𝓕.FieldOpFreeAlgebra) (h : a ≈ b) :
ι 𝓝ᶠ(a) = ι 𝓝ᶠ(b) := by
rw [equiv_iff_sub_mem_ideal] at h
rw [LinearMap.sub_mem_ker_iff.mp]
simp only [LinearMap.mem_ker, ← map_sub]
exact ι_normalOrderF_zero_of_mem_ideal (a - b) h
/-- Normal ordering on `FieldOpAlgebra`. -/
noncomputable def normalOrder : FieldOpAlgebra 𝓕 →ₗ[] FieldOpAlgebra 𝓕 where
toFun := Quotient.lift (ι.toLinearMap ∘ₗ normalOrderF) ι_normalOrderF_eq_of_equiv
map_add' x y := by
obtain ⟨x, rfl⟩ := ι_surjective x
obtain ⟨y, rfl⟩ := ι_surjective y
rw [← map_add, ι_apply, ι_apply, ι_apply]
rw [Quotient.lift_mk, Quotient.lift_mk, Quotient.lift_mk]
simp
map_smul' c y := by
obtain ⟨y, rfl⟩ := ι_surjective y
rw [← map_smul, ι_apply, ι_apply]
simp
@[inherit_doc normalOrder]
scoped[FieldSpecification.FieldOpAlgebra] notation "𝓝(" a ")" => normalOrder a
/-!
## Properties of normal ordering.
-/
@ -532,14 +313,13 @@ noncomputable def contractStateAtIndex (φ : 𝓕.FieldOp) (φs : List 𝓕.Fiel
| some n => 𝓢(𝓕 |>ₛ φ, 𝓕 |>ₛ (φs.take n)) • [anPart φ, ofFieldOp φs[n]]ₛ
/--
Within a proto-operator algebra,
`φ * N(φ₀φ₁…φₙ) = N(φφ₀φ₁…φₙ) + ∑ i, (sᵢ • [anPartF φ, φᵢ]ₛ) * N(φ₀φ₁…φᵢ₋₁φᵢ₊₁…φₙ)`,
where `sₙ` is the exchange sign for `φ` and `φ₀φ₁…φᵢ₋₁`.
For a field specification `𝓕`, the following relation holds in the algebra `𝓕.FieldOpAlgebra`,
`φ * 𝓝(φ₀φ₁…φₙ) = 𝓝(φφ₀φ₁…φₙ) + ∑ i, (𝓢(φ,φ₀φ₁…φᵢ₋₁) • [anPartF φ, φᵢ]ₛ) * 𝓝(φ₀φ₁…φᵢ₋₁φᵢ₊₁…φₙ)`.
-/
lemma ofFieldOp_mul_normalOrder_ofFieldOpList_eq_sum (φ : 𝓕.FieldOp)
(φs : List 𝓕.FieldOp) : ofFieldOp φ * 𝓝(ofFieldOpList φs) =
lemma ofFieldOp_mul_normalOrder_ofFieldOpList_eq_sum (φ : 𝓕.FieldOp) (φs : List 𝓕.FieldOp) :
ofFieldOp φ * 𝓝(ofFieldOpList φs) =
∑ n : Option (Fin φs.length), contractStateAtIndex φ φs n *
𝓝(ofFieldOpList (HepLean.List.optionEraseZ φs φ n)) := by
𝓝(ofFieldOpList (optionEraseZ φs φ n)) := by
rw [ofFieldOp_mul_normalOrder_ofFieldOpList_eq_superCommute]
rw [anPart_superCommute_normalOrder_ofFieldOpList_sum]
simp only [instCommGroup.eq_1, Fin.getElem_fin, Algebra.smul_mul_assoc, contractStateAtIndex,

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@ -0,0 +1,118 @@
/-
Copyright (c) 2025 Joseph Tooby-Smith. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.
Authors: Joseph Tooby-Smith
-/
import HepLean.PerturbationTheory.FieldOpAlgebra.NormalOrder.Lemmas
import HepLean.PerturbationTheory.WickContraction.InsertAndContract
/-!
# Normal ordering with relation to Wick contractions
-/
namespace FieldSpecification
open FieldOpFreeAlgebra
open HepLean.List
open FieldStatistic
open WickContraction
namespace FieldOpAlgebra
variable {𝓕 : FieldSpecification}
/-!
## Normal order of uncontracted terms within proto-algebra.
-/
/--
Let `c` be a Wick Contraction for `φs := φ₀φ₁…φₙ`.
We have (roughly) `𝓝ᶠ([φsΛ ↩Λ φ i none]ᵘᶜ) = s • 𝓝ᶠ(φ :: [φsΛ]ᵘᶜ)`
Where `s` is the exchange sign for `φ` and the uncontracted fields in `φ₀φ₁…φᵢ₋₁`.
-/
lemma normalOrder_uncontracted_none (φ : 𝓕.FieldOp) (φs : List 𝓕.FieldOp)
(i : Fin φs.length.succ) (φsΛ : WickContraction φs.length) :
𝓝(ofFieldOpList [φsΛ ↩Λ φ i none]ᵘᶜ)
= 𝓢(𝓕 |>ₛ φ, 𝓕 |>ₛ ⟨φs.get, φsΛ.uncontracted.filter (fun x => i.succAbove x < i)⟩) •
𝓝(ofFieldOpList (φ :: [φsΛ]ᵘᶜ)) := by
simp only [Nat.succ_eq_add_one, instCommGroup.eq_1]
rw [ofFieldOpList_normalOrder_insert φ [φsΛ]ᵘᶜ
⟨(φsΛ.uncontractedListOrderPos i), by simp [uncontractedListGet]⟩, smul_smul]
trans (1 : ) • (𝓝(ofFieldOpList [φsΛ ↩Λ φ i none]ᵘᶜ))
· simp
congr 1
simp only [instCommGroup.eq_1, uncontractedListGet]
rw [← List.map_take, take_uncontractedListOrderPos_eq_filter]
have h1 : (𝓕 |>ₛ List.map φs.get (List.filter (fun x => decide (↑x < i.1)) φsΛ.uncontractedList))
= 𝓕 |>ₛ ⟨φs.get, (φsΛ.uncontracted.filter (fun x => x.val < i.1))⟩ := by
simp only [Nat.succ_eq_add_one, ofFinset]
congr
rw [uncontractedList_eq_sort]
have hdup : (List.filter (fun x => decide (x.1 < i.1))
(Finset.sort (fun x1 x2 => x1 ≤ x2) φsΛ.uncontracted)).Nodup := by
exact List.Nodup.filter _ (Finset.sort_nodup (fun x1 x2 => x1 ≤ x2) φsΛ.uncontracted)
have hsort : (List.filter (fun x => decide (x.1 < i.1))
(Finset.sort (fun x1 x2 => x1 ≤ x2) φsΛ.uncontracted)).Sorted (· ≤ ·) := by
exact List.Sorted.filter _ (Finset.sort_sorted (fun x1 x2 => x1 ≤ x2) φsΛ.uncontracted)
rw [← (List.toFinset_sort (· ≤ ·) hdup).mpr hsort]
congr
ext a
simp
rw [h1]
simp only [Nat.succ_eq_add_one]
have h2 : (Finset.filter (fun x => x.1 < i.1) φsΛ.uncontracted) =
(Finset.filter (fun x => i.succAbove x < i) φsΛ.uncontracted) := by
ext a
simp only [Nat.succ_eq_add_one, Finset.mem_filter, and_congr_right_iff]
intro ha
simp only [Fin.succAbove]
split
· apply Iff.intro
· intro h
omega
· intro h
rename_i h
rw [Fin.lt_def] at h
simp only [Fin.coe_castSucc] at h
omega
· apply Iff.intro
· intro h
rename_i h'
rw [Fin.lt_def]
simp only [Fin.val_succ]
rw [Fin.lt_def] at h'
simp only [Fin.coe_castSucc, not_lt] at h'
omega
· intro h
rename_i h
rw [Fin.lt_def] at h
simp only [Fin.val_succ] at h
omega
rw [h2]
simp only [exchangeSign_mul_self]
congr
simp only [Nat.succ_eq_add_one]
rw [insertAndContract_uncontractedList_none_map]
/--
Let `c` be a Wick Contraction for `φ₀φ₁…φₙ`.
We have (roughly) `N(c ↩Λ φ i k).uncontractedList`
is equal to `N((c.uncontractedList).eraseIdx k')`
where `k'` is the position in `c.uncontractedList` corresponding to `k`.
-/
lemma normalOrder_uncontracted_some (φ : 𝓕.FieldOp) (φs : List 𝓕.FieldOp)
(i : Fin φs.length.succ) (φsΛ : WickContraction φs.length) (k : φsΛ.uncontracted) :
𝓝(ofFieldOpList [φsΛ ↩Λ φ i (some k)]ᵘᶜ)
= 𝓝(ofFieldOpList (optionEraseZ [φsΛ]ᵘᶜ φ ((uncontractedFieldOpEquiv φs φsΛ) k))) := by
simp only [Nat.succ_eq_add_one, insertAndContract, optionEraseZ, uncontractedFieldOpEquiv,
Equiv.optionCongr_apply, Equiv.coe_trans, Option.map_some', Function.comp_apply, finCongr_apply,
Fin.coe_cast, uncontractedListGet]
congr
rw [congr_uncontractedList]
erw [uncontractedList_extractEquiv_symm_some]
simp only [Fin.coe_succAboveEmb, List.map_eraseIdx, List.map_map]
congr
conv_rhs => rw [get_eq_insertIdx_succAbove φ φs i]
end FieldOpAlgebra
end FieldSpecification

View file

@ -3,9 +3,10 @@ Copyright (c) 2025 Joseph Tooby-Smith. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.
Authors: Joseph Tooby-Smith
-/
import HepLean.PerturbationTheory.FieldOpAlgebra.NormalOrder.WickContractions
import HepLean.PerturbationTheory.WickContraction.Sign.InsertNone
import HepLean.PerturbationTheory.WickContraction.Sign.InsertSome
import HepLean.PerturbationTheory.WickContraction.StaticContract
import HepLean.PerturbationTheory.FieldOpAlgebra.WicksTheorem
import HepLean.Meta.Remark.Basic
/-!
# Static Wick's theorem
@ -29,11 +30,16 @@ lemma static_wick_theorem_nil : ofFieldOpList [] = ∑ (φsΛ : WickContraction
/--
The static Wicks theorem states that
`φ₀…φₙ` is equal to the sum of
`φsΛ.1.sign • φsΛ.1.staticContract * 𝓝(ofFieldOpList [φsΛ.1]ᵘᶜ)`
`φ₀…φₙ` is equal to
`∑ φsΛ, φsΛ.1.sign • φsΛ.1.staticContract * 𝓝(ofFieldOpList [φsΛ.1]ᵘᶜ)`
over all Wick contraction `φsΛ`.
This is compared to the ordinary Wicks theorem in which `staticContract` is replaced with
`timeContract`.
The proof is via induction on `φs`. The base case `φs = []` is handled by `static_wick_theorem_nil`.
The inductive step works as follows:
- The proof considers `φ₀…φₙ` as `φ₀(φ₁…φₙ)` and use the induction hypothesis on `φ₁…φₙ`.
- It also uses `ofFieldOp_mul_normalOrder_ofFieldOpList_eq_sum`
-/
theorem static_wick_theorem : (φs : List 𝓕.FieldOp) →
ofFieldOpList φs = ∑ (φsΛ : WickContraction φs.length),

View file

@ -3,7 +3,7 @@ Copyright (c) 2025 Joseph Tooby-Smith. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.
Authors: Joseph Tooby-Smith
-/
import HepLean.PerturbationTheory.FieldOpAlgebra.NormalOrder
import HepLean.PerturbationTheory.FieldOpAlgebra.NormalOrder.Lemmas
import HepLean.PerturbationTheory.FieldOpAlgebra.TimeOrder
/-!

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@ -0,0 +1,215 @@
/-
Copyright (c) 2025 Joseph Tooby-Smith. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.
Authors: Joseph Tooby-Smith
-/
import HepLean.PerturbationTheory.WickContraction.Sign.Basic
import HepLean.PerturbationTheory.WickContraction.Sign.InsertNone
import HepLean.PerturbationTheory.WickContraction.Sign.InsertSome
import HepLean.PerturbationTheory.WickContraction.TimeContract
import HepLean.PerturbationTheory.FieldOpAlgebra.NormalOrder.WickContractions
/-!
# Wick term
-/
open FieldSpecification
variable {𝓕 : FieldSpecification}
namespace WickContraction
variable {n : } (c : WickContraction n)
open HepLean.List
open FieldOpAlgebra
open FieldStatistic
noncomputable section
/-- For a Wick contraction `φsΛ`, we define `wickTerm φsΛ` to be the element of `𝓕.FieldOpAlgebra`
given by `φsΛ.sign • φsΛ.timeContract * 𝓝([φsΛ]ᵘᶜ)`. -/
def wickTerm {φs : List 𝓕.FieldOp} (φsΛ : WickContraction φs.length) : 𝓕.FieldOpAlgebra :=
φsΛ.sign • φsΛ.timeContract * 𝓝(ofFieldOpList [φsΛ]ᵘᶜ)
/--
Let `φsΛ` be a Wick Contraction for `φs = φ₀φ₁…φₙ`. Then the wick-term of ` (φsΛ ↩Λ φ i none)`
```(φsΛ ↩Λ φ i none).sign • (φsΛ ↩Λ φ i none).timeContract 𝓞 * 𝓞.crAnF 𝓝ᶠ([φsΛ ↩Λ φ i none]ᵘᶜ)```
is equal to
`s • (φsΛ.sign • φsΛ.timeContract 𝓞 * 𝓞.crAnF 𝓝ᶠ(φ :: [φsΛ]ᵘᶜ))`
where `s` is the exchange sign of `φ` and the uncontracted fields in `φ₀φ₁…φᵢ₋₁`.
The proof of this result relies primarily on:
- `normalOrderF_uncontracted_none` which replaces `𝓝ᶠ([φsΛ ↩Λ φ i none]ᵘᶜ)` with
`𝓝ᶠ(φ :: [φsΛ]ᵘᶜ)` up to a sign.
- `timeContract_insertAndContract_none` which replaces `(φsΛ ↩Λ φ i none).timeContract 𝓞` with
`φsΛ.timeContract 𝓞`.
- `sign_insert_none` and `signInsertNone_eq_filterset` which are used to take account of
signs.
-/
lemma wickTerm_none_eq_wick_term_cons (φ : 𝓕.FieldOp) (φs : List 𝓕.FieldOp)
(i : Fin φs.length.succ) (φsΛ : WickContraction φs.length) :
(φsΛ ↩Λ φ i none).wickTerm =
𝓢(𝓕 |>ₛ φ, 𝓕 |>ₛ ⟨φs.get, (Finset.univ.filter (fun k => i.succAbove k < i))⟩)
• (φsΛ.sign • φsΛ.timeContract * 𝓝(ofFieldOpList (φ :: [φsΛ]ᵘᶜ))) := by
rw [wickTerm]
by_cases hg : GradingCompliant φs φsΛ
· rw [normalOrder_uncontracted_none, sign_insert_none]
simp only [Nat.succ_eq_add_one, timeContract_insertAndContract_none, instCommGroup.eq_1,
Algebra.mul_smul_comm, Algebra.smul_mul_assoc, smul_smul]
congr 1
rw [← mul_assoc]
congr 1
rw [signInsertNone_eq_filterset _ _ _ _ hg, ← map_mul]
congr
rw [ofFinset_union]
congr
ext a
simp only [Finset.mem_sdiff, Finset.mem_union, Finset.mem_filter, Finset.mem_univ, true_and,
Finset.mem_inter, not_and, not_lt, and_imp]
apply Iff.intro
· intro ha
have ha1 := ha.1
rcases ha1 with ha1 | ha1
· exact ha1.2
· exact ha1.2
· intro ha
simp only [uncontracted, Finset.mem_filter, Finset.mem_univ, true_and, ha, and_true,
forall_const]
have hx : φsΛ.getDual? a = none ↔ ¬ (φsΛ.getDual? a).isSome := by
simp
rw [hx]
simp only [Bool.not_eq_true, Bool.eq_false_or_eq_true_self, true_and]
intro h1 h2
simp_all
· simp only [Nat.succ_eq_add_one, timeContract_insertAndContract_none, Algebra.smul_mul_assoc,
instCommGroup.eq_1]
rw [timeContract_of_not_gradingCompliant]
simp only [ZeroMemClass.coe_zero, zero_mul, smul_zero]
exact hg
/--
Let `c` be a Wick Contraction for `φ₀φ₁…φₙ`.
This lemma states that
`(c.sign • c.timeContract 𝓞) * N(c.uncontracted)`
for `c` equal to `c ↩Λ φ i (some k)` is equal to that for just `c`
mulitiplied by the exchange sign of `φ` and `φ₀φ₁…φᵢ₋₁`.
-/
lemma wickTerm_some_eq_wick_term_optionEraseZ (φ : 𝓕.FieldOp) (φs : List 𝓕.FieldOp)
(i : Fin φs.length.succ) (φsΛ : WickContraction φs.length) (k : φsΛ.uncontracted)
(hlt : ∀ (k : Fin φs.length), timeOrderRel φ φs[k])
(hn : ∀ (k : Fin φs.length), i.succAbove k < i → ¬ timeOrderRel φs[k] φ) :
(φsΛ ↩Λ φ i (some k)).wickTerm =
𝓢(𝓕 |>ₛ φ, 𝓕 |>ₛ ⟨φs.get, (Finset.univ.filter (fun x => i.succAbove x < i))⟩)
• (φsΛ.sign • (contractStateAtIndex φ [φsΛ]ᵘᶜ
((uncontractedFieldOpEquiv φs φsΛ) (some k)) * φsΛ.timeContract)
* 𝓝(ofFieldOpList (optionEraseZ [φsΛ]ᵘᶜ φ (uncontractedFieldOpEquiv φs φsΛ k)))) := by
rw [wickTerm]
by_cases hg : GradingCompliant φs φsΛ ∧ (𝓕 |>ₛ φ) = (𝓕 |>ₛ φs[k.1])
· by_cases hk : i.succAbove k < i
· rw [WickContraction.timeConract_insertAndContract_some_eq_mul_contractStateAtIndex_not_lt]
swap
· exact hn _ hk
rw [normalOrder_uncontracted_some, sign_insert_some]
simp only [instCommGroup.eq_1, smul_smul, Algebra.smul_mul_assoc]
congr 1
rw [mul_assoc, mul_comm (sign φs φsΛ), ← mul_assoc]
congr 1
exact signInsertSome_mul_filter_contracted_of_lt φ φs φsΛ i k hk hg
· omega
· have hik : i.succAbove ↑k ≠ i := Fin.succAbove_ne i ↑k
rw [timeContract_insertAndContract_some_eq_mul_contractStateAtIndex_lt]
swap
· exact hlt _
rw [normalOrder_uncontracted_some]
rw [sign_insert_some]
simp only [instCommGroup.eq_1, smul_smul, Algebra.smul_mul_assoc]
congr 1
rw [mul_assoc, mul_comm (sign φs φsΛ), ← mul_assoc]
congr 1
exact signInsertSome_mul_filter_contracted_of_not_lt φ φs φsΛ i k hk hg
· omega
· rw [timeConract_insertAndContract_some]
simp only [Fin.getElem_fin, not_and] at hg
by_cases hg' : GradingCompliant φs φsΛ
· have hg := hg hg'
simp only [Nat.succ_eq_add_one, Fin.getElem_fin, ite_mul, Algebra.smul_mul_assoc,
instCommGroup.eq_1, contractStateAtIndex, uncontractedFieldOpEquiv, Equiv.optionCongr_apply,
Equiv.coe_trans, Option.map_some', Function.comp_apply, finCongr_apply, Fin.coe_cast,
List.getElem_map, uncontractedList_getElem_uncontractedIndexEquiv_symm, List.get_eq_getElem,
uncontractedListGet]
by_cases h1 : i < i.succAbove ↑k
· simp only [h1, ↓reduceIte, MulMemClass.coe_mul]
rw [timeContract_zero_of_diff_grade]
simp only [zero_mul, smul_zero]
rw [superCommute_anPart_ofFieldOpF_diff_grade_zero]
simp only [zero_mul, smul_zero]
exact hg
exact hg
· simp only [h1, ↓reduceIte, MulMemClass.coe_mul]
rw [timeContract_zero_of_diff_grade]
simp only [zero_mul, smul_zero]
rw [superCommute_anPart_ofFieldOpF_diff_grade_zero]
simp only [zero_mul, smul_zero]
exact hg
exact fun a => hg (id (Eq.symm a))
· rw [timeContract_of_not_gradingCompliant]
simp only [Nat.succ_eq_add_one, Fin.getElem_fin, mul_zero, ZeroMemClass.coe_zero, smul_zero,
zero_mul, instCommGroup.eq_1]
exact hg'
/--
Given a Wick contraction `φsΛ` of `φs = φ₀φ₁…φₙ` and an `i`, we have that
`(φsΛ.sign • φsΛ.timeContract 𝓞) * 𝓞.crAnF (φ * 𝓝ᶠ([φsΛ]ᵘᶜ))`
is equal to the product of
- the exchange sign of `φ` and `φ₀φ₁…φᵢ₋₁`,
- the sum of `((φsΛ ↩Λ φ i k).sign • (φsΛ ↩Λ φ i k).timeContract 𝓞) * 𝓞.crAnF 𝓝ᶠ([φsΛ ↩Λ φ i k]ᵘᶜ)`
over all `k` in `Option φsΛ.uncontracted`.
The proof of this result primarily depends on
- `crAnF_ofFieldOpF_mul_normalOrderF_ofFieldOpFsList_eq_sum` to rewrite `𝓞.crAnF (φ * 𝓝ᶠ([φsΛ]ᵘᶜ))`
- `wick_term_none_eq_wick_term_cons`
- `wick_term_some_eq_wick_term_optionEraseZ`
-/
lemma wickTerm_cons_eq_sum_wick_term (φ : 𝓕.FieldOp) (φs : List 𝓕.FieldOp) (i : Fin φs.length.succ)
(φsΛ : WickContraction φs.length) (hlt : ∀ (k : Fin φs.length), timeOrderRel φ φs[k])
(hn : ∀ (k : Fin φs.length), i.succAbove k < i → ¬timeOrderRel φs[k] φ) :
ofFieldOp φ * φsΛ.wickTerm =
𝓢(𝓕 |>ₛ φ, 𝓕 |>ₛ ⟨φs.get, (Finset.univ.filter (fun x => i.succAbove x < i))⟩) •
∑ (k : Option φsΛ.uncontracted), (φsΛ ↩Λ φ i k).wickTerm := by
trans (φsΛ.sign • φsΛ.timeContract) * ((ofFieldOp φ) * 𝓝(ofFieldOpList [φsΛ]ᵘᶜ))
· have ht := Subalgebra.mem_center_iff.mp (Subalgebra.smul_mem (Subalgebra.center _)
(WickContraction.timeContract φsΛ).2 (φsΛ.sign))
rw [wickTerm]
rw [← mul_assoc, ht, mul_assoc]
rw [ofFieldOp_mul_normalOrder_ofFieldOpList_eq_sum, Finset.mul_sum,
uncontractedFieldOpEquiv_list_sum, Finset.smul_sum]
simp only [instCommGroup.eq_1, Nat.succ_eq_add_one]
congr 1
funext n
match n with
| none =>
rw [wickTerm_none_eq_wick_term_cons]
simp only [contractStateAtIndex, uncontractedFieldOpEquiv, Equiv.optionCongr_apply,
Equiv.coe_trans, Option.map_none', one_mul, Algebra.smul_mul_assoc, instCommGroup.eq_1,
smul_smul]
congr 1
rw [← mul_assoc, exchangeSign_mul_self]
simp
| some n =>
rw [wickTerm_some_eq_wick_term_optionEraseZ _ _ _ _ _
(fun k => hlt k) (fun k a => hn k a)]
simp only [uncontractedFieldOpEquiv, Equiv.optionCongr_apply, Equiv.coe_trans, Option.map_some',
Function.comp_apply, finCongr_apply, Algebra.smul_mul_assoc, instCommGroup.eq_1, smul_smul]
congr 1
· rw [← mul_assoc, exchangeSign_mul_self]
rw [one_mul]
· rw [← mul_assoc]
congr 1
have ht := (WickContraction.timeContract φsΛ).prop
rw [@Subalgebra.mem_center_iff] at ht
rw [ht]
end
end WickContraction

View file

@ -6,6 +6,8 @@ Authors: Joseph Tooby-Smith
import HepLean.PerturbationTheory.WickContraction.TimeContract
import HepLean.PerturbationTheory.WickContraction.Sign.InsertNone
import HepLean.PerturbationTheory.WickContraction.Sign.InsertSome
import HepLean.PerturbationTheory.FieldOpAlgebra.NormalOrder.WickContractions
import HepLean.PerturbationTheory.FieldOpAlgebra.WickTerm
import HepLean.Meta.Remark.Basic
/-!
@ -28,289 +30,10 @@ open FieldStatistic
/-!
## Normal order of uncontracted terms within proto-algebra.
-/
/--
Let `c` be a Wick Contraction for `φs := φ₀φ₁…φₙ`.
We have (roughly) `𝓝ᶠ([φsΛ ↩Λ φ i none]ᵘᶜ) = s • 𝓝ᶠ(φ :: [φsΛ]ᵘᶜ)`
Where `s` is the exchange sign for `φ` and the uncontracted fields in `φ₀φ₁…φᵢ₋₁`.
-/
lemma normalOrder_uncontracted_none (φ : 𝓕.FieldOp) (φs : List 𝓕.FieldOp)
(i : Fin φs.length.succ) (φsΛ : WickContraction φs.length) :
𝓝(ofFieldOpList [φsΛ ↩Λ φ i none]ᵘᶜ)
= 𝓢(𝓕 |>ₛ φ, 𝓕 |>ₛ ⟨φs.get, φsΛ.uncontracted.filter (fun x => i.succAbove x < i)⟩) •
𝓝(ofFieldOpList (φ :: [φsΛ]ᵘᶜ)) := by
simp only [Nat.succ_eq_add_one, instCommGroup.eq_1]
rw [ofFieldOpList_normalOrder_insert φ [φsΛ]ᵘᶜ
⟨(φsΛ.uncontractedListOrderPos i), by simp [uncontractedListGet]⟩, smul_smul]
trans (1 : ) • (𝓝(ofFieldOpList [φsΛ ↩Λ φ i none]ᵘᶜ))
· simp
congr 1
simp only [instCommGroup.eq_1, uncontractedListGet]
rw [← List.map_take, take_uncontractedListOrderPos_eq_filter]
have h1 : (𝓕 |>ₛ List.map φs.get (List.filter (fun x => decide (↑x < i.1)) φsΛ.uncontractedList))
= 𝓕 |>ₛ ⟨φs.get, (φsΛ.uncontracted.filter (fun x => x.val < i.1))⟩ := by
simp only [Nat.succ_eq_add_one, ofFinset]
congr
rw [uncontractedList_eq_sort]
have hdup : (List.filter (fun x => decide (x.1 < i.1))
(Finset.sort (fun x1 x2 => x1 ≤ x2) φsΛ.uncontracted)).Nodup := by
exact List.Nodup.filter _ (Finset.sort_nodup (fun x1 x2 => x1 ≤ x2) φsΛ.uncontracted)
have hsort : (List.filter (fun x => decide (x.1 < i.1))
(Finset.sort (fun x1 x2 => x1 ≤ x2) φsΛ.uncontracted)).Sorted (· ≤ ·) := by
exact List.Sorted.filter _ (Finset.sort_sorted (fun x1 x2 => x1 ≤ x2) φsΛ.uncontracted)
rw [← (List.toFinset_sort (· ≤ ·) hdup).mpr hsort]
congr
ext a
simp
rw [h1]
simp only [Nat.succ_eq_add_one]
have h2 : (Finset.filter (fun x => x.1 < i.1) φsΛ.uncontracted) =
(Finset.filter (fun x => i.succAbove x < i) φsΛ.uncontracted) := by
ext a
simp only [Nat.succ_eq_add_one, Finset.mem_filter, and_congr_right_iff]
intro ha
simp only [Fin.succAbove]
split
· apply Iff.intro
· intro h
omega
· intro h
rename_i h
rw [Fin.lt_def] at h
simp only [Fin.coe_castSucc] at h
omega
· apply Iff.intro
· intro h
rename_i h'
rw [Fin.lt_def]
simp only [Fin.val_succ]
rw [Fin.lt_def] at h'
simp only [Fin.coe_castSucc, not_lt] at h'
omega
· intro h
rename_i h
rw [Fin.lt_def] at h
simp only [Fin.val_succ] at h
omega
rw [h2]
simp only [exchangeSign_mul_self]
congr
simp only [Nat.succ_eq_add_one]
rw [insertAndContract_uncontractedList_none_map]
/--
Let `c` be a Wick Contraction for `φ₀φ₁…φₙ`.
We have (roughly) `N(c ↩Λ φ i k).uncontractedList`
is equal to `N((c.uncontractedList).eraseIdx k')`
where `k'` is the position in `c.uncontractedList` corresponding to `k`.
-/
lemma normalOrder_uncontracted_some (φ : 𝓕.FieldOp) (φs : List 𝓕.FieldOp)
(i : Fin φs.length.succ) (φsΛ : WickContraction φs.length) (k : φsΛ.uncontracted) :
𝓝(ofFieldOpList [φsΛ ↩Λ φ i (some k)]ᵘᶜ)
= 𝓝(ofFieldOpList (optionEraseZ [φsΛ]ᵘᶜ φ ((uncontractedFieldOpEquiv φs φsΛ) k))) := by
simp only [Nat.succ_eq_add_one, insertAndContract, optionEraseZ, uncontractedFieldOpEquiv,
Equiv.optionCongr_apply, Equiv.coe_trans, Option.map_some', Function.comp_apply, finCongr_apply,
Fin.coe_cast, uncontractedListGet]
congr
rw [congr_uncontractedList]
erw [uncontractedList_extractEquiv_symm_some]
simp only [Fin.coe_succAboveEmb, List.map_eraseIdx, List.map_map]
congr
conv_rhs => rw [get_eq_insertIdx_succAbove φ φs i]
/-!
## Wick terms
-/
remark wick_term_terminology := "
Let `φsΛ` be a Wick contraction. We informally call the term
`(φsΛ.sign • φsΛ.timeContract 𝓞) * 𝓞.crAnF 𝓝ᶠ([φsΛ]ᵘᶜ)` the Wick term
associated with `φsΛ`. We do not make this a fully-fledge definition, as
in most cases we want to consider slight modifications of this term."
/--
Let `φsΛ` be a Wick Contraction for `φs = φ₀φ₁…φₙ`. Then the wick-term of ` (φsΛ ↩Λ φ i none)`
```(φsΛ ↩Λ φ i none).sign • (φsΛ ↩Λ φ i none).timeContract 𝓞 * 𝓞.crAnF 𝓝ᶠ([φsΛ ↩Λ φ i none]ᵘᶜ)```
is equal to
`s • (φsΛ.sign • φsΛ.timeContract 𝓞 * 𝓞.crAnF 𝓝ᶠ(φ :: [φsΛ]ᵘᶜ))`
where `s` is the exchange sign of `φ` and the uncontracted fields in `φ₀φ₁…φᵢ₋₁`.
The proof of this result relies primarily on:
- `normalOrderF_uncontracted_none` which replaces `𝓝ᶠ([φsΛ ↩Λ φ i none]ᵘᶜ)` with
`𝓝ᶠ(φ :: [φsΛ]ᵘᶜ)` up to a sign.
- `timeContract_insertAndContract_none` which replaces `(φsΛ ↩Λ φ i none).timeContract 𝓞` with
`φsΛ.timeContract 𝓞`.
- `sign_insert_none` and `signInsertNone_eq_filterset` which are used to take account of
signs.
-/
lemma wick_term_none_eq_wick_term_cons (φ : 𝓕.FieldOp) (φs : List 𝓕.FieldOp)
(i : Fin φs.length.succ) (φsΛ : WickContraction φs.length) :
(φsΛ ↩Λ φ i none).sign • (φsΛ ↩Λ φ i none).timeContract
* 𝓝(ofFieldOpList [φsΛ ↩Λ φ i none]ᵘᶜ) =
𝓢(𝓕 |>ₛ φ, 𝓕 |>ₛ ⟨φs.get, (Finset.univ.filter (fun k => i.succAbove k < i))⟩)
• (φsΛ.sign • φsΛ.timeContract * 𝓝(ofFieldOpList (φ :: [φsΛ]ᵘᶜ))) := by
by_cases hg : GradingCompliant φs φsΛ
· rw [normalOrder_uncontracted_none, sign_insert_none]
simp only [Nat.succ_eq_add_one, timeContract_insertAndContract_none, instCommGroup.eq_1,
Algebra.mul_smul_comm, Algebra.smul_mul_assoc, smul_smul]
congr 1
rw [← mul_assoc]
congr 1
rw [signInsertNone_eq_filterset _ _ _ _ hg, ← map_mul]
congr
rw [ofFinset_union]
congr
ext a
simp only [Finset.mem_sdiff, Finset.mem_union, Finset.mem_filter, Finset.mem_univ, true_and,
Finset.mem_inter, not_and, not_lt, and_imp]
apply Iff.intro
· intro ha
have ha1 := ha.1
rcases ha1 with ha1 | ha1
· exact ha1.2
· exact ha1.2
· intro ha
simp only [uncontracted, Finset.mem_filter, Finset.mem_univ, true_and, ha, and_true,
forall_const]
have hx : φsΛ.getDual? a = none ↔ ¬ (φsΛ.getDual? a).isSome := by
simp
rw [hx]
simp only [Bool.not_eq_true, Bool.eq_false_or_eq_true_self, true_and]
intro h1 h2
simp_all
· simp only [Nat.succ_eq_add_one, timeContract_insertAndContract_none, Algebra.smul_mul_assoc,
instCommGroup.eq_1]
rw [timeContract_of_not_gradingCompliant]
simp only [ZeroMemClass.coe_zero, zero_mul, smul_zero]
exact hg
/--
Let `c` be a Wick Contraction for `φ₀φ₁…φₙ`.
This lemma states that
`(c.sign • c.timeContract 𝓞) * N(c.uncontracted)`
for `c` equal to `c ↩Λ φ i (some k)` is equal to that for just `c`
mulitiplied by the exchange sign of `φ` and `φ₀φ₁…φᵢ₋₁`.
-/
lemma wick_term_some_eq_wick_term_optionEraseZ (φ : 𝓕.FieldOp) (φs : List 𝓕.FieldOp)
(i : Fin φs.length.succ) (φsΛ : WickContraction φs.length) (k : φsΛ.uncontracted)
(hlt : ∀ (k : Fin φs.length), timeOrderRel φ φs[k])
(hn : ∀ (k : Fin φs.length), i.succAbove k < i → ¬ timeOrderRel φs[k] φ) :
(φsΛ ↩Λ φ i (some k)).sign • (φsΛ ↩Λ φ i (some k)).timeContract
* 𝓝(ofFieldOpList [φsΛ ↩Λ φ i (some k)]ᵘᶜ) =
𝓢(𝓕 |>ₛ φ, 𝓕 |>ₛ ⟨φs.get, (Finset.univ.filter (fun x => i.succAbove x < i))⟩)
• (φsΛ.sign • (contractStateAtIndex φ [φsΛ]ᵘᶜ
((uncontractedFieldOpEquiv φs φsΛ) (some k)) * φsΛ.timeContract)
* 𝓝(ofFieldOpList (optionEraseZ [φsΛ]ᵘᶜ φ (uncontractedFieldOpEquiv φs φsΛ k)))) := by
by_cases hg : GradingCompliant φs φsΛ ∧ (𝓕 |>ₛ φ) = (𝓕 |>ₛ φs[k.1])
· by_cases hk : i.succAbove k < i
· rw [WickContraction.timeConract_insertAndContract_some_eq_mul_contractStateAtIndex_not_lt]
swap
· exact hn _ hk
rw [normalOrder_uncontracted_some, sign_insert_some]
simp only [instCommGroup.eq_1, smul_smul, Algebra.smul_mul_assoc]
congr 1
rw [mul_assoc, mul_comm (sign φs φsΛ), ← mul_assoc]
congr 1
exact signInsertSome_mul_filter_contracted_of_lt φ φs φsΛ i k hk hg
· omega
· have hik : i.succAbove ↑k ≠ i := Fin.succAbove_ne i ↑k
rw [WickContraction.timeConract_insertAndContract_some_eq_mul_contractStateAtIndex_lt]
swap
· exact hlt _
rw [normalOrder_uncontracted_some]
rw [sign_insert_some]
simp only [instCommGroup.eq_1, smul_smul, Algebra.smul_mul_assoc]
congr 1
rw [mul_assoc, mul_comm (sign φs φsΛ), ← mul_assoc]
congr 1
exact signInsertSome_mul_filter_contracted_of_not_lt φ φs φsΛ i k hk hg
· omega
· rw [timeConract_insertAndContract_some]
simp only [Fin.getElem_fin, not_and] at hg
by_cases hg' : GradingCompliant φs φsΛ
· have hg := hg hg'
simp only [Nat.succ_eq_add_one, Fin.getElem_fin, ite_mul, Algebra.smul_mul_assoc,
instCommGroup.eq_1, contractStateAtIndex, uncontractedFieldOpEquiv, Equiv.optionCongr_apply,
Equiv.coe_trans, Option.map_some', Function.comp_apply, finCongr_apply, Fin.coe_cast,
List.getElem_map, uncontractedList_getElem_uncontractedIndexEquiv_symm, List.get_eq_getElem,
uncontractedListGet]
by_cases h1 : i < i.succAbove ↑k
· simp only [h1, ↓reduceIte, MulMemClass.coe_mul]
rw [timeContract_zero_of_diff_grade]
simp only [zero_mul, smul_zero]
rw [superCommute_anPart_ofFieldOpF_diff_grade_zero]
simp only [zero_mul, smul_zero]
exact hg
exact hg
· simp only [h1, ↓reduceIte, MulMemClass.coe_mul]
rw [timeContract_zero_of_diff_grade]
simp only [zero_mul, smul_zero]
rw [superCommute_anPart_ofFieldOpF_diff_grade_zero]
simp only [zero_mul, smul_zero]
exact hg
exact fun a => hg (id (Eq.symm a))
· rw [timeContract_of_not_gradingCompliant]
simp only [Nat.succ_eq_add_one, Fin.getElem_fin, mul_zero, ZeroMemClass.coe_zero, smul_zero,
zero_mul, instCommGroup.eq_1]
exact hg'
/--
Given a Wick contraction `φsΛ` of `φs = φ₀φ₁…φₙ` and an `i`, we have that
`(φsΛ.sign • φsΛ.timeContract 𝓞) * 𝓞.crAnF (φ * 𝓝ᶠ([φsΛ]ᵘᶜ))`
is equal to the product of
- the exchange sign of `φ` and `φ₀φ₁…φᵢ₋₁`,
- the sum of `((φsΛ ↩Λ φ i k).sign • (φsΛ ↩Λ φ i k).timeContract 𝓞) * 𝓞.crAnF 𝓝ᶠ([φsΛ ↩Λ φ i k]ᵘᶜ)`
over all `k` in `Option φsΛ.uncontracted`.
The proof of this result primarily depends on
- `crAnF_ofFieldOpF_mul_normalOrderF_ofFieldOpFsList_eq_sum` to rewrite `𝓞.crAnF (φ * 𝓝ᶠ([φsΛ]ᵘᶜ))`
- `wick_term_none_eq_wick_term_cons`
- `wick_term_some_eq_wick_term_optionEraseZ`
-/
lemma wick_term_cons_eq_sum_wick_term (φ : 𝓕.FieldOp) (φs : List 𝓕.FieldOp) (i : Fin φs.length.succ)
(φsΛ : WickContraction φs.length) (hlt : ∀ (k : Fin φs.length), timeOrderRel φ φs[k])
(hn : ∀ (k : Fin φs.length), i.succAbove k < i → ¬timeOrderRel φs[k] φ) :
(φsΛ.sign • φsΛ.timeContract) * ((ofFieldOp φ) * 𝓝(ofFieldOpList [φsΛ]ᵘᶜ)) =
𝓢(𝓕 |>ₛ φ, 𝓕 |>ₛ ⟨φs.get, (Finset.univ.filter (fun x => i.succAbove x < i))⟩) •
∑ (k : Option φsΛ.uncontracted), ((φsΛ ↩Λ φ i k).sign •
(φsΛ ↩Λ φ i k).timeContract * (𝓝(ofFieldOpList [φsΛ ↩Λ φ i k]ᵘᶜ))) := by
rw [ofFieldOp_mul_normalOrder_ofFieldOpList_eq_sum, Finset.mul_sum,
uncontractedFieldOpEquiv_list_sum, Finset.smul_sum]
simp only [instCommGroup.eq_1, Nat.succ_eq_add_one]
congr 1
funext n
match n with
| none =>
rw [wick_term_none_eq_wick_term_cons]
simp only [contractStateAtIndex, uncontractedFieldOpEquiv, Equiv.optionCongr_apply,
Equiv.coe_trans, Option.map_none', one_mul, Algebra.smul_mul_assoc, instCommGroup.eq_1,
smul_smul]
congr 1
rw [← mul_assoc, exchangeSign_mul_self]
simp
| some n =>
rw [wick_term_some_eq_wick_term_optionEraseZ _ _ _ _ _
(fun k => hlt k) (fun k a => hn k a)]
simp only [uncontractedFieldOpEquiv, Equiv.optionCongr_apply, Equiv.coe_trans, Option.map_some',
Function.comp_apply, finCongr_apply, Algebra.smul_mul_assoc, instCommGroup.eq_1, smul_smul]
congr 1
· rw [← mul_assoc, exchangeSign_mul_self]
rw [one_mul]
· rw [← mul_assoc]
congr 1
have ht := (WickContraction.timeContract φsΛ).prop
rw [@Subalgebra.mem_center_iff] at ht
rw [ht]
/-!
## Wick's theorem
@ -335,9 +58,8 @@ lemma wicks_theorem_nil :
rfl
lemma wicks_theorem_congr {φs φs' : List 𝓕.FieldOp} (h : φs = φs') :
∑ (φsΛ : WickContraction φs.length), (φsΛ.sign • φsΛ.timeContract) * 𝓝(ofFieldOpList [φsΛ]ᵘᶜ)
= ∑ (φs'Λ : WickContraction φs'.length), (φs'Λ.sign • φs'Λ.timeContract) *
𝓝(ofFieldOpList [φs'Λ]ᵘᶜ) := by
∑ (φsΛ : WickContraction φs.length), φsΛ.wickTerm
= ∑ (φs'Λ : WickContraction φs'.length), φs'Λ.wickTerm := by
subst h
simp
@ -356,17 +78,21 @@ remark wicks_theorem_context := "
The statement of these theorems for bosons is simplier then when fermions are involved, since
one does not have to worry about the minus-signs picked up on exchanging fields."
/-- Wick's theorem for time-ordered products of bosonic and fermionic fields.
The time ordered product `T(φ₀φ₁…φₙ)` is equal to the sum of terms,
for all possible Wick contractions `c` of the list of fields `φs := φ₀φ₁…φₙ`, given by
the multiple of:
- The sign corresponding to the number of fermionic-fermionic exchanges one must do
to put elements in contracted pairs of `c` next to each other.
- The product of time-contractions of the contracted pairs of `c`.
- The normal-ordering of the uncontracted fields in `c`.
/-- Wick's theorem states that for a list of fields `φs = φ₀…φₙ`
`𝓣(φs) = ∑ φsΛ, (φsΛ.sign • φsΛ.timeContract) * 𝓝([φsΛ]ᵘᶜ)`
where the sum is over all Wick contractions `φsΛ` of `φs`.
The proof is via induction on `φs`. The base case `φs = []` is handled by `wicks_theorem_nil`.
The inductive step works as follows:
- The lemma `timeOrder_eq_maxTimeField_mul_finset` is used to write
`𝓣(φ₀…φₙ)` as ` 𝓢(φᵢ,φ₀…φᵢ₋₁) • φᵢ * 𝓣(φ₀…φᵢ₋₁φᵢ₊₁φₙ)` where `φᵢ` is
the maximal time field in `φ₀…φₙ`.
- The induction hypothesis is used to expand `𝓣(φ₀…φᵢ₋₁φᵢ₊₁φₙ)` as a sum over Wick contractions of
`φ₀…φᵢ₋₁φᵢ₊₁φₙ`.
- Further the lemmas `wick_term_cons_eq_sum_wick_term` and `insertLift_sum` are used.
-/
theorem wicks_theorem : (φs : List 𝓕.FieldOp) → 𝓣(ofFieldOpList φs) =
∑ (φsΛ : WickContraction φs.length), (φsΛ.sign • φsΛ.timeContract) * 𝓝(ofFieldOpList [φsΛ]ᵘᶜ)
∑ (φsΛ : WickContraction φs.length), φsΛ.wickTerm
| [] => wicks_theorem_nil
| φ :: φs => by
have ih := wicks_theorem (eraseMaxTimeField φ φs)
@ -380,18 +106,10 @@ theorem wicks_theorem : (φs : List 𝓕.FieldOp) → 𝓣(ofFieldOpList φs) =
conv_rhs => rw [insertLift_sum]
apply Finset.sum_congr rfl
intro c _
have ht := Subalgebra.mem_center_iff.mp (Subalgebra.smul_mem (Subalgebra.center _)
(WickContraction.timeContract c).2 (sign (eraseMaxTimeField φ φs) c))
rw [Algebra.smul_mul_assoc, ← mul_assoc, ht, mul_assoc]
rw [wick_term_cons_eq_sum_wick_term
rw [Algebra.smul_mul_assoc, wickTerm_cons_eq_sum_wick_term
(maxTimeField φ φs) (eraseMaxTimeField φ φs) (maxTimeFieldPosFin φ φs) c]
trans (1 : ) • ∑ k : Option { x // x ∈ c.uncontracted }, sign
(List.insertIdx (↑(maxTimeFieldPosFin φ φs)) (maxTimeField φ φs) (eraseMaxTimeField φ φs))
(c ↩Λ (maxTimeField φ φs) (maxTimeFieldPosFin φ φs) k) •
↑((c ↩Λ (maxTimeField φ φs) (maxTimeFieldPosFin φ φs) k).timeContract) *
𝓝(ofFieldOpList (List.map (List.insertIdx (↑(maxTimeFieldPosFin φ φs))
(maxTimeField φ φs) (eraseMaxTimeField φ φs)).get
(c ↩Λ (maxTimeField φ φs) (maxTimeFieldPosFin φ φs) k).uncontractedList))
trans (1 : ) • ∑ k : Option { x // x ∈ c.uncontracted },
(c ↩Λ (maxTimeField φ φs) (maxTimeFieldPosFin φ φs) k).wickTerm
swap
· simp [uncontractedListGet]
rw [smul_smul]

View file

@ -3,10 +3,10 @@ Copyright (c) 2025 Joseph Tooby-Smith. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.
Authors: Joseph Tooby-Smith
-/
import HepLean.PerturbationTheory.WickContraction.TimeCond
import HepLean.PerturbationTheory.WickContraction.Sign.Join
import HepLean.PerturbationTheory.FieldOpAlgebra.StaticWickTheorem
import HepLean.Meta.Remark.Basic
import HepLean.PerturbationTheory.FieldOpAlgebra.WicksTheorem
import HepLean.PerturbationTheory.WickContraction.Sign.Join
import HepLean.PerturbationTheory.WickContraction.TimeCond
/-!
# Wick's theorem for normal ordered lists
@ -21,7 +21,7 @@ open WickContraction
open EqTimeOnly
lemma timeOrder_ofFieldOpList_eqTimeOnly (φs : List 𝓕.FieldOp) :
timeOrder (ofFieldOpList φs) = ∑ (φsΛ : {φsΛ // φsΛ.EqTimeOnly (φs := φs)}),
𝓣(ofFieldOpList φs) = ∑ (φsΛ : {φsΛ // φsΛ.EqTimeOnly (φs := φs)}),
φsΛ.1.sign • φsΛ.1.timeContract.1 * 𝓣(𝓝(ofFieldOpList [φsΛ.1]ᵘᶜ)) := by
rw [static_wick_theorem φs]
let e2 : WickContraction φs.length ≃
@ -86,6 +86,7 @@ lemma normalOrder_timeOrder_ofFieldOpList_eq_haveEqTime_sum_not_haveEqTime (φs
φsΛ.1.sign • φsΛ.1.timeContract.1 * 𝓣(𝓝(ofFieldOpList [φsΛ.1]ᵘᶜ)) := by
rw [normalOrder_timeOrder_ofFieldOpList_eq_eqTimeOnly_empty]
rw [wicks_theorem]
simp only [wickTerm]
let e1 : WickContraction φs.length ≃ {φsΛ // HaveEqTime φsΛ} ⊕ {φsΛ // ¬ HaveEqTime φsΛ} := by
exact (Equiv.sumCompl HaveEqTime).symm
rw [← e1.symm.sum_comp]
@ -143,7 +144,8 @@ lemma normalOrder_timeOrder_ofFieldOpList_eq_not_haveEqTime_sub_inductive (φs :
lemma wicks_theorem_normal_order_empty : 𝓣(𝓝(ofFieldOpList [])) =
∑ (φsΛ : {φsΛ : WickContraction ([] : List 𝓕.FieldOp).length // ¬ HaveEqTime φsΛ}),
φsΛ.1.sign • φsΛ.1.timeContract.1 * 𝓝(ofFieldOpList [φsΛ.1]ᵘᶜ) := by
φsΛ.1.wickTerm := by
simp only [wickTerm]
let e2 : {φsΛ : WickContraction ([] : List 𝓕.FieldOp).length // ¬ HaveEqTime φsΛ} ≃ Unit :=
{
toFun := fun x => (),
@ -176,16 +178,17 @@ lemma wicks_theorem_normal_order_empty : 𝓣(𝓝(ofFieldOpList [])) =
/--
Wicks theorem for normal ordering followed by time-ordering, states that
`𝓣(𝓝(φ₀…φₙ))` is equal to the sum over
`φsΛ.1.sign • φsΛ.1.timeContract.1 * 𝓝(ofFieldOpList [φsΛ.1]ᵘᶜ)`
for those Wick contraction `φsΛ` which do not have any equal time contractions.
`𝓣(𝓝(φ₀…φₙ))` is equal to
`∑ φsΛ, φsΛ.1.sign • φsΛ.1.timeContract.1 * 𝓝(ofFieldOpList [φsΛ.1]ᵘᶜ)`
over those Wick contraction `φsΛ` which do not have any equal time contractions.
This is compared to the ordinary Wicks theorem which sums over all Wick contractions.
-/
theorem wicks_theorem_normal_order : (φs : List 𝓕.FieldOp) →
𝓣(𝓝(ofFieldOpList φs)) = ∑ (φsΛ : {φsΛ : WickContraction φs.length // ¬ HaveEqTime φsΛ}),
φsΛ.1.sign • φsΛ.1.timeContract.1 * 𝓝(ofFieldOpList [φsΛ.1]ᵘᶜ)
𝓣(𝓝(ofFieldOpList φs)) =
∑ (φsΛ : {φsΛ : WickContraction φs.length // ¬ HaveEqTime φsΛ}), φsΛ.1.wickTerm
| [] => wicks_theorem_normal_order_empty
| φ :: φs => by
simp only [wickTerm]
rw [normalOrder_timeOrder_ofFieldOpList_eq_not_haveEqTime_sub_inductive]
simp only [Algebra.smul_mul_assoc, ne_eq, add_right_eq_self]
apply Finset.sum_eq_zero
@ -194,7 +197,7 @@ theorem wicks_theorem_normal_order : (φs : List 𝓕.FieldOp) →
right
have ih := wicks_theorem_normal_order [φsΛ.1]ᵘᶜ
rw [ih]
simp
simp [wickTerm]
termination_by φs => φs.length
decreasing_by
simp only [uncontractedListGet, List.length_cons, List.length_map, gt_iff_lt]

View file

@ -3,8 +3,7 @@ Copyright (c) 2025 Joseph Tooby-Smith. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.
Authors: Joseph Tooby-Smith
-/
import HepLean.PerturbationTheory.FieldOpAlgebra.NormalOrder
import HepLean.Mathematics.List.InsertIdx
import HepLean.PerturbationTheory.FieldSpecification.Basic
/-!
# Wick contractions

View file

@ -34,8 +34,7 @@ noncomputable def timeContract {φs : List 𝓕.FieldOp}
This result follows from the fact that `timeContract` only depends on contracted pairs,
and `(φsΛ ↩Λ φ i none)` has the 'same' contracted pairs as `φsΛ`. -/
@[simp]
lemma timeContract_insertAndContract_none
(φ : 𝓕.FieldOp) (φs : List 𝓕.FieldOp)
lemma timeContract_insertAndContract_none (φ : 𝓕.FieldOp) (φs : List 𝓕.FieldOp)
(φsΛ : WickContraction φs.length) (i : Fin φs.length.succ) :
(φsΛ ↩Λ φ i none).timeContract = φsΛ.timeContract := by
rw [timeContract, insertAndContract_none_prod_contractions]
@ -78,7 +77,7 @@ lemma timeContract_empty (φs : List 𝓕.FieldOp) :
open FieldStatistic
lemma timeConract_insertAndContract_some_eq_mul_contractStateAtIndex_lt
lemma timeContract_insertAndContract_some_eq_mul_contractStateAtIndex_lt
(φ : 𝓕.FieldOp) (φs : List 𝓕.FieldOp)
(φsΛ : WickContraction φs.length) (i : Fin φs.length.succ) (k : φsΛ.uncontracted)
(ht : 𝓕.timeOrderRel φ φs[k.1]) (hik : i < i.succAbove k) :

View file

@ -145,6 +145,7 @@ def perturbationTheory : Note where
.name `FieldSpecification.FieldOpFreeAlgebra.superCommuteF,
.h2 "Field-operator algebra",
.name `FieldSpecification.FieldOpAlgebra,
.name `FieldSpecification.FieldOpAlgebra.fieldOpAlgebraGrade,
.name `FieldSpecification.FieldOpAlgebra.superCommute,
.h1 "Time ordering",
.name `FieldSpecification.crAnTimeOrderRel,
@ -169,14 +170,13 @@ def perturbationTheory : Note where
.name `WickContraction.join,
.h2 "Sign",
.name `WickContraction.sign,
.name `WickContraction.join_sign,
.name `WickContraction.signInsertNone_eq_filterset,
.name `WickContraction.signInsertSome_mul_filter_contracted_of_not_lt,
.name `WickContraction.join_sign,
.h2 "Cardinality",
.name `WickContraction.card_eq_cardFun,
.h1 "Time and static contractions",
.h1 "Useful results",
.h1 "The three Wick's theorems",
.name `FieldSpecification.wicks_theorem,
.name `FieldSpecification.FieldOpAlgebra.static_wick_theorem,