docs: Update docs related to Wick's theorem

This commit is contained in:
jstoobysmith 2025-02-05 10:36:48 +00:00
parent d61cc2ee4d
commit 759f204ed5
3 changed files with 32 additions and 10 deletions

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@ -216,6 +216,11 @@ lemma anPart_mul_normalOrder_ofFieldOpList_eq_superCommute (φ : 𝓕.FieldOp)
-/
/--
The proof of this result ultimetly depends on
- `superCommuteF_ofCrAnListF_ofFieldOpListF_eq_sum`
- `normalOrderSign_eraseIdx`
-/
lemma ofCrAnFieldOp_superCommute_normalOrder_ofCrAnFieldOpList_sum (φ : 𝓕.CrAnFieldOp)
(φs : List 𝓕.CrAnFieldOp) : [ofCrAnFieldOp φ, 𝓝(ofCrAnFieldOpList φs)]ₛ = ∑ n : Fin φs.length,
𝓢(𝓕 |>ₛ φ, 𝓕 |>ₛ (φs.take n)) • [ofCrAnFieldOp φ, ofCrAnFieldOp φs[n]]ₛ
@ -329,6 +334,9 @@ noncomputable def contractStateAtIndex (φ : 𝓕.FieldOp) (φs : List 𝓕.Fiel
/--
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)`.
The proof of this ultimently depends on :
- `ofCrAnFieldOp_superCommute_normalOrder_ofCrAnFieldOpList_sum`
-/
lemma ofFieldOp_mul_normalOrder_ofFieldOpList_eq_sum (φ : 𝓕.FieldOp) (φs : List 𝓕.FieldOp) :
ofFieldOp φ * 𝓝(ofFieldOpList φs) =

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@ -164,17 +164,16 @@ lemma wickTerm_insert_some (φ : 𝓕.FieldOp) (φs : List 𝓕.FieldOp)
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`.
Let `φsΛ` be a Wick contraction for `φs = φ₀φ₁…φₙ`. Let `φ` be a field with time
greater then or equal to all the fields in `φs`. Let `i` be a in `Fin φs.length.succ` such that
all files in `φ₀…φᵢ₋₁` have time strictly less then `φ`. Then
`φ * φsΛ.wickTerm = 𝓢(φ, φ₀…φᵢ₋₁) • ∑ k, (φsΛ ↩Λ φ i k).wickTerm`
where the sum is over all `k` in `Option φsΛ.uncontracted` (so either `none` or `some k`).
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`
The proof of proceeds as follows:
- `ofFieldOp_mul_normalOrder_ofFieldOpList_eq_sum` is used to expand `φ 𝓝([φsΛ]ᵘᶜ)` as
a sum over `k` in `Option φsΛ.uncontracted` of terms involving `[φ, φs[k]]` etc.
- Then `wickTerm_insert_none` and `wickTerm_insert_some` are used to equate terms.
-/
lemma mul_wickTerm_eq_sum (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])

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@ -143,6 +143,7 @@ def perturbationTheory : Note where
.name `FieldSpecification.FieldOpFreeAlgebra.ofFieldOpListF,
.name `FieldSpecification.FieldOpFreeAlgebra.fieldOpFreeAlgebraGrade,
.name `FieldSpecification.FieldOpFreeAlgebra.superCommuteF,
.name `FieldSpecification.FieldOpFreeAlgebra.superCommuteF_ofCrAnListF_ofFieldOpListF_eq_sum,
.h2 "Field-operator algebra",
.name `FieldSpecification.FieldOpAlgebra,
.name `FieldSpecification.FieldOpAlgebra.fieldOpAlgebraGrade,
@ -158,6 +159,10 @@ def perturbationTheory : Note where
.name `FieldSpecification.normalOrderSign,
.name `FieldSpecification.FieldOpFreeAlgebra.normalOrderF,
.name `FieldSpecification.FieldOpAlgebra.normalOrder,
.h2 "Some lemmas",
.name `FieldSpecification.normalOrderSign_eraseIdx,
.name `FieldSpecification.FieldOpAlgebra.ofCrAnFieldOp_superCommute_normalOrder_ofCrAnFieldOpList_sum,
.name `FieldSpecification.FieldOpAlgebra.ofFieldOp_mul_normalOrder_ofFieldOpList_eq_sum,
.h1 "Wick Contractions",
.h2 "Definition",
.name `WickContraction,
@ -179,6 +184,16 @@ def perturbationTheory : Note where
.h1 "Time and static contractions",
.h1 "Wick terms",
.name `WickContraction.wickTerm,
.name `WickContraction.wickTerm_empty_nil,
.name `WickContraction.wickTerm_insert_none,
.name `WickContraction.wickTerm_insert_some,
.name `WickContraction.mul_wickTerm_eq_sum,
.h1 "Static wick terms",
.name `WickContraction.staticWickTerm,
.name `WickContraction.staticWickTerm_empty_nil,
.name `WickContraction.staticWickTerm_insert_zero_none,
.name `WickContraction.staticWickTerm_insert_zero_some,
.name `WickContraction.mul_staticWickTerm_eq_sum,
.h1 "The three Wick's theorems",
.name `FieldSpecification.wicks_theorem,
.name `FieldSpecification.FieldOpAlgebra.static_wick_theorem,