PhysLean/HepLean/Tensors/ComplexLorentz/PauliMatrices/CoContractContr.lean
2024-10-29 13:46:18 +00:00

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/-
Copyright (c) 2024 Joseph Tooby-Smith. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.
Authors: Joseph Tooby-Smith
-/
import HepLean.Tensors.ComplexLorentz.PauliMatrices.Basis
import HepLean.Tensors.ComplexLorentz.Lemmas
/-!
## Contractiong of indices of Pauli matrix.
The main result of this file is `pauliMatrix_contract_pauliMatrix` which states that
`η_{μν} σ^{μ α dot β} σ^{ν α' dot β'} = 2 ε^{αα'} ε^{dot β dot β'}`.
The current way this result is proved is by using tensor tree manipulations.
There is likely a more direct path to this result.
-/
open IndexNotation
open CategoryTheory
open MonoidalCategory
open Matrix
open MatrixGroups
open Complex
open TensorProduct
open IndexNotation
open CategoryTheory
open TensorTree
open OverColor.Discrete
noncomputable section
namespace complexLorentzTensor
open Fermion
/-- The map to colors one gets when contracting the 4-vector indices pauli matrices. -/
def pauliMatrixContrPauliMatrixMap := ((Sum.elim
((Sum.elim ![Color.down, Color.down] ![Color.up, Color.upL, Color.upR] ∘ ⇑finSumFinEquiv.symm) ∘
Fin.succAbove 1 ∘ Fin.succAbove 1) ![Color.up, Color.upL, Color.upR] ∘ ⇑finSumFinEquiv.symm) ∘
Fin.succAbove 0 ∘ Fin.succAbove 2)
lemma pauliMatrix_contr_lower_0_0_0 :
{(basisVector pauliCoMap (fun | 0 => 0 | 1 => 0 | 2 => 0)) | μ α β ⊗
pauliContr | μ α' β'}ᵀ.tensor =
basisVector pauliMatrixContrPauliMatrixMap (fun | 0 => 0 | 1 => 0 | 2 => 0 | 3 => 0)
+ basisVector pauliMatrixContrPauliMatrixMap (fun | 0 => 0 | 1 => 0 | 2 => 1 | 3 => 1) := by
conv =>
lhs
rw [basis_contr_pauliMatrix_basis_tree_expand_tensor]
conv =>
lhs; lhs; lhs; lhs; lhs; lhs; lhs; lhs
rw [contrBasisVectorMul_pos (by decide)]
conv =>
lhs; lhs; lhs; lhs; lhs; lhs; lhs; rhs; lhs
rw [contrBasisVectorMul_pos (by decide)]
conv =>
lhs; lhs; lhs; lhs; lhs; lhs; rhs; lhs
rw [contrBasisVectorMul_neg (by decide)]
conv =>
lhs; lhs; lhs; lhs; lhs; rhs; lhs
rw [contrBasisVectorMul_neg (by decide)]
conv =>
lhs; lhs; lhs; lhs; rhs; rhs; lhs
rw [contrBasisVectorMul_neg (by decide)]
conv =>
lhs; lhs; lhs; rhs; rhs; lhs
rw [contrBasisVectorMul_neg (by decide)]
conv =>
lhs; lhs; rhs; lhs;
rw [contrBasisVectorMul_neg (by decide)]
conv =>
lhs; rhs; rhs; lhs;
rw [contrBasisVectorMul_neg (by decide)]
conv =>
lhs
simp only [_root_.zero_smul, one_smul, _root_.smul_zero, _root_.add_zero, _root_.zero_add]
rw [basisVectorContrPauli, basisVectorContrPauli]
/- Simplifying. -/
congr 1
· congr 1
funext k
fin_cases k <;> rfl
· congr 1
funext k
fin_cases k <;> rfl
lemma pauliMatrix_contr_lower_0_1_1 :
{(basisVector pauliCoMap (fun | 0 => 0 | 1 => 1 | 2 => 1)) | μ α β ⊗
pauliContr | μ α' β'}ᵀ.tensor =
basisVector pauliMatrixContrPauliMatrixMap (fun | 0 => 1 | 1 => 1 | 2 => 0 | 3 => 0)
+ basisVector pauliMatrixContrPauliMatrixMap (fun | 0 => 1 | 1 => 1 | 2 => 1 | 3 => 1) := by
conv =>
lhs
rw [basis_contr_pauliMatrix_basis_tree_expand_tensor]
conv =>
lhs; lhs; lhs; lhs; lhs; lhs; lhs; lhs
rw [contrBasisVectorMul_pos (by decide)]
conv =>
lhs; lhs; lhs; lhs; lhs; lhs; lhs; rhs; lhs
rw [contrBasisVectorMul_pos (by decide)]
conv =>
lhs; lhs; lhs; lhs; lhs; lhs; rhs; lhs
rw [contrBasisVectorMul_neg (by decide)]
conv =>
lhs; lhs; lhs; lhs; lhs; rhs; lhs
rw [contrBasisVectorMul_neg (by decide)]
conv =>
lhs; lhs; lhs; lhs; rhs; rhs; lhs
rw [contrBasisVectorMul_neg (by decide)]
conv =>
lhs; lhs; lhs; rhs; rhs; lhs
rw [contrBasisVectorMul_neg (by decide)]
conv =>
lhs; lhs; rhs; lhs;
rw [contrBasisVectorMul_neg (by decide)]
conv =>
lhs; rhs; rhs; lhs;
rw [contrBasisVectorMul_neg (by decide)]
conv =>
lhs
simp only [_root_.zero_smul, one_smul, _root_.smul_zero, _root_.add_zero, _root_.zero_add]
rw [basisVectorContrPauli, basisVectorContrPauli]
/- Simplifying. -/
congr 1
· congr 1
funext k
fin_cases k <;> rfl
· congr 1
funext k
fin_cases k <;> rfl
lemma pauliMatrix_contr_lower_1_0_1 :
{(basisVector pauliCoMap (fun | 0 => 1 | 1 => 0 | 2 => 1)) | μ α β ⊗
pauliContr | μ α' β'}ᵀ.tensor =
basisVector pauliMatrixContrPauliMatrixMap (fun | 0 => 0 | 1 => 1 | 2 => 0 | 3 => 1)
+ basisVector pauliMatrixContrPauliMatrixMap (fun | 0 => 0 | 1 => 1 | 2 => 1 | 3 => 0) := by
conv =>
lhs
rw [basis_contr_pauliMatrix_basis_tree_expand_tensor]
conv =>
lhs; lhs; lhs; lhs; lhs; lhs; lhs; lhs
rw [contrBasisVectorMul_neg (by decide)]
conv =>
lhs; lhs; lhs; lhs; lhs; lhs; lhs; rhs; lhs
rw [contrBasisVectorMul_neg (by decide)]
conv =>
lhs; lhs; lhs; lhs; lhs; lhs; rhs; lhs
rw [contrBasisVectorMul_pos (by decide)]
conv =>
lhs; lhs; lhs; lhs; lhs; rhs; lhs
rw [contrBasisVectorMul_pos (by decide)]
conv =>
lhs; lhs; lhs; lhs; rhs; rhs; lhs
rw [contrBasisVectorMul_neg (by decide)]
conv =>
lhs; lhs; lhs; rhs; rhs; lhs
rw [contrBasisVectorMul_neg (by decide)]
conv =>
lhs; lhs; rhs; lhs;
rw [contrBasisVectorMul_neg (by decide)]
conv =>
lhs; rhs; rhs; lhs;
rw [contrBasisVectorMul_neg (by decide)]
conv =>
lhs
simp only [_root_.zero_smul, one_smul, _root_.smul_zero, _root_.add_zero, _root_.zero_add]
rw [basisVectorContrPauli, basisVectorContrPauli]
/- Simplifying. -/
congr 1
· congr 1
funext k
fin_cases k <;> rfl
· congr 1
funext k
fin_cases k <;> rfl
lemma pauliMatrix_contr_lower_1_1_0 :
{(basisVector pauliCoMap (fun | 0 => 1 | 1 => 1 | 2 => 0)) | μ α β ⊗
pauliContr | μ α' β'}ᵀ.tensor =
basisVector pauliMatrixContrPauliMatrixMap (fun | 0 => 1 | 1 => 0 | 2 => 0 | 3 => 1)
+ basisVector pauliMatrixContrPauliMatrixMap (fun | 0 => 1 | 1 => 0 | 2 => 1 | 3 => 0) := by
conv =>
lhs
rw [basis_contr_pauliMatrix_basis_tree_expand_tensor]
conv =>
lhs; lhs; lhs; lhs; lhs; lhs; lhs; lhs
rw [contrBasisVectorMul_neg (by decide)]
conv =>
lhs; lhs; lhs; lhs; lhs; lhs; lhs; rhs; lhs
rw [contrBasisVectorMul_neg (by decide)]
conv =>
lhs; lhs; lhs; lhs; lhs; lhs; rhs; lhs
rw [contrBasisVectorMul_pos (by decide)]
conv =>
lhs; lhs; lhs; lhs; lhs; rhs; lhs
rw [contrBasisVectorMul_pos (by decide)]
conv =>
lhs; lhs; lhs; lhs; rhs; rhs; lhs
rw [contrBasisVectorMul_neg (by decide)]
conv =>
lhs; lhs; lhs; rhs; rhs; lhs
rw [contrBasisVectorMul_neg (by decide)]
conv =>
lhs; lhs; rhs; lhs;
rw [contrBasisVectorMul_neg (by decide)]
conv =>
lhs; rhs; rhs; lhs;
rw [contrBasisVectorMul_neg (by decide)]
conv =>
lhs
simp only [_root_.zero_smul, one_smul, _root_.smul_zero, _root_.add_zero, _root_.zero_add]
rw [basisVectorContrPauli, basisVectorContrPauli]
/- Simplifying. -/
congr 1
· congr 1
funext k
fin_cases k <;> rfl
· congr 1
funext k
fin_cases k <;> rfl
lemma pauliMatrix_contr_lower_2_0_1 :
{(basisVector pauliCoMap (fun | 0 => 2 | 1 => 0 | 2 => 1)) | μ α β ⊗
pauliContr | μ α' β'}ᵀ.tensor =
(-I) • basisVector pauliMatrixContrPauliMatrixMap (fun | 0 => 0 | 1 => 1 | 2 => 0 | 3 => 1)
+ (I) •
basisVector pauliMatrixContrPauliMatrixMap (fun | 0 => 0 | 1 => 1 | 2 => 1 | 3 => 0) := by
conv =>
lhs
rw [basis_contr_pauliMatrix_basis_tree_expand_tensor]
conv =>
lhs; lhs; lhs; lhs; lhs; lhs; lhs; lhs
rw [contrBasisVectorMul_neg (by decide)]
conv =>
lhs; lhs; lhs; lhs; lhs; lhs; lhs; rhs; lhs
rw [contrBasisVectorMul_neg (by decide)]
conv =>
lhs; lhs; lhs; lhs; lhs; lhs; rhs; lhs
rw [contrBasisVectorMul_neg (by decide)]
conv =>
lhs; lhs; lhs; lhs; lhs; rhs; lhs
rw [contrBasisVectorMul_neg (by decide)]
conv =>
lhs; lhs; lhs; lhs; rhs; rhs; lhs
rw [contrBasisVectorMul_pos (by decide)]
conv =>
lhs; lhs; lhs; rhs; rhs; lhs
rw [contrBasisVectorMul_pos (by decide)]
conv =>
lhs; lhs; rhs; lhs;
rw [contrBasisVectorMul_neg (by decide)]
conv =>
lhs; rhs; rhs; lhs;
rw [contrBasisVectorMul_neg (by decide)]
conv =>
lhs
simp only [_root_.zero_smul, one_smul, _root_.smul_zero, _root_.add_zero, _root_.zero_add]
rw [basisVectorContrPauli, basisVectorContrPauli]
/- Simplifying. -/
congr 1
· congr 2
funext k
fin_cases k <;> rfl
· congr 2
funext k
fin_cases k <;> rfl
lemma pauliMatrix_contr_lower_2_1_0 :
{(basisVector pauliCoMap (fun | 0 => 2 | 1 => 1 | 2 => 0)) | μ α β ⊗
pauliContr | μ α' β'}ᵀ.tensor =
(-I) • basisVector pauliMatrixContrPauliMatrixMap (fun | 0 => 1 | 1 => 0 | 2 => 0 | 3 => 1)
+ (I) •
basisVector pauliMatrixContrPauliMatrixMap (fun | 0 => 1 | 1 => 0 | 2 => 1 | 3 => 0) := by
conv =>
lhs
rw [basis_contr_pauliMatrix_basis_tree_expand_tensor]
conv =>
lhs; lhs; lhs; lhs; lhs; lhs; lhs; lhs
rw [contrBasisVectorMul_neg (by decide)]
conv =>
lhs; lhs; lhs; lhs; lhs; lhs; lhs; rhs; lhs
rw [contrBasisVectorMul_neg (by decide)]
conv =>
lhs; lhs; lhs; lhs; lhs; lhs; rhs; lhs
rw [contrBasisVectorMul_neg (by decide)]
conv =>
lhs; lhs; lhs; lhs; lhs; rhs; lhs
rw [contrBasisVectorMul_neg (by decide)]
conv =>
lhs; lhs; lhs; lhs; rhs; rhs; lhs
rw [contrBasisVectorMul_pos (by decide)]
conv =>
lhs; lhs; lhs; rhs; rhs; lhs
rw [contrBasisVectorMul_pos (by decide)]
conv =>
lhs; lhs; rhs; lhs;
rw [contrBasisVectorMul_neg (by decide)]
conv =>
lhs; rhs; rhs; lhs;
rw [contrBasisVectorMul_neg (by decide)]
conv =>
lhs
simp only [_root_.zero_smul, one_smul, _root_.smul_zero, _root_.add_zero, _root_.zero_add]
rw [basisVectorContrPauli, basisVectorContrPauli]
/- Simplifying. -/
congr 1
· congr 2
funext k
fin_cases k <;> rfl
· congr 2
funext k
fin_cases k <;> rfl
lemma pauliMatrix_contr_lower_3_0_0 :
{(basisVector pauliCoMap (fun | 0 => 3 | 1 => 0 | 2 => 0)) | μ α β ⊗
pauliContr | μ α' β'}ᵀ.tensor =
basisVector pauliMatrixContrPauliMatrixMap (fun | 0 => 0 | 1 => 0 | 2 => 0 | 3 => 0)
+ (-1 : ) • basisVector pauliMatrixContrPauliMatrixMap
(fun | 0 => 0 | 1 => 0 | 2 => 1 | 3 => 1) := by
conv =>
lhs
rw [basis_contr_pauliMatrix_basis_tree_expand_tensor]
conv =>
lhs; lhs; lhs; lhs; lhs; lhs; lhs; lhs
rw [contrBasisVectorMul_neg (by decide)]
conv =>
lhs; lhs; lhs; lhs; lhs; lhs; lhs; rhs; lhs
rw [contrBasisVectorMul_neg (by decide)]
conv =>
lhs; lhs; lhs; lhs; lhs; lhs; rhs; lhs
rw [contrBasisVectorMul_neg (by decide)]
conv =>
lhs; lhs; lhs; lhs; lhs; rhs; lhs
rw [contrBasisVectorMul_neg (by decide)]
conv =>
lhs; lhs; lhs; lhs; rhs; rhs; lhs
rw [contrBasisVectorMul_neg (by decide)]
conv =>
lhs; lhs; lhs; rhs; rhs; lhs
rw [contrBasisVectorMul_neg (by decide)]
conv =>
lhs; lhs; rhs; lhs;
rw [contrBasisVectorMul_pos (by decide)]
conv =>
lhs; rhs; rhs; lhs;
rw [contrBasisVectorMul_pos (by decide)]
conv =>
lhs
simp only [_root_.zero_smul, one_smul, _root_.smul_zero, _root_.add_zero, _root_.zero_add]
rw [basisVectorContrPauli, basisVectorContrPauli]
/- Simplifying. -/
congr 1
· congr 2
funext k
fin_cases k <;> rfl
· congr 2
funext k
fin_cases k <;> rfl
lemma pauliMatrix_contr_lower_3_1_1 :
{(basisVector pauliCoMap (fun | 0 => 3 | 1 => 1 | 2 => 1)) | μ α β ⊗
pauliContr | μ α' β'}ᵀ.tensor =
basisVector pauliMatrixContrPauliMatrixMap (fun | 0 => 1 | 1 => 1 | 2 => 0 | 3 => 0)
+ (-1 : ) •
basisVector pauliMatrixContrPauliMatrixMap (fun | 0 => 1 | 1 => 1 | 2 => 1 | 3 => 1) := by
conv =>
lhs
rw [basis_contr_pauliMatrix_basis_tree_expand_tensor]
conv =>
lhs; lhs; lhs; lhs; lhs; lhs; lhs; lhs
rw [contrBasisVectorMul_neg (by decide)]
conv =>
lhs; lhs; lhs; lhs; lhs; lhs; lhs; rhs; lhs
rw [contrBasisVectorMul_neg (by decide)]
conv =>
lhs; lhs; lhs; lhs; lhs; lhs; rhs; lhs
rw [contrBasisVectorMul_neg (by decide)]
conv =>
lhs; lhs; lhs; lhs; lhs; rhs; lhs
rw [contrBasisVectorMul_neg (by decide)]
conv =>
lhs; lhs; lhs; lhs; rhs; rhs; lhs
rw [contrBasisVectorMul_neg (by decide)]
conv =>
lhs; lhs; lhs; rhs; rhs; lhs
rw [contrBasisVectorMul_neg (by decide)]
conv =>
lhs; lhs; rhs; lhs;
rw [contrBasisVectorMul_pos (by decide)]
conv =>
lhs; rhs; rhs; lhs;
rw [contrBasisVectorMul_pos (by decide)]
conv =>
lhs
simp only [_root_.zero_smul, one_smul, _root_.smul_zero, _root_.add_zero, _root_.zero_add]
rw [basisVectorContrPauli, basisVectorContrPauli]
/- Simplifying. -/
congr 1
· congr 2
funext k
fin_cases k <;> rfl
· congr 2
funext k
fin_cases k <;> rfl
/-! TODO: Work out why `pauliCo_prod_basis_expand'` is needed. -/
/-- This lemma is exactly the same as `pauliCo_prod_basis_expand`.
It is needed here for `pauliMatrix_contract_pauliMatrix_aux`. It is unclear why
`pauliMatrix_lower_basis_expand_prod` does not work. -/
private lemma pauliCo_prod_basis_expand' {n : } {c : Fin n → complexLorentzTensor.C}
(t : TensorTree complexLorentzTensor c) :
(TensorTree.prod (tensorNode pauliCo) t).tensor =
((((tensorNode
(basisVector pauliCoMap fun | 0 => 0 | 1 => 0 | 2 => 0)).prod t).add
(((tensorNode
(basisVector pauliCoMap fun | 0 => 0 | 1 => 1 | 2 => 1)).prod t).add
((TensorTree.smul (-1) ((tensorNode
(basisVector pauliCoMap fun | 0 => 1 | 1 => 0 | 2 => 1)).prod t)).add
((TensorTree.smul (-1) ((tensorNode
(basisVector pauliCoMap fun | 0 => 1 | 1 => 1 | 2 => 0)).prod t)).add
((TensorTree.smul I ((tensorNode
(basisVector pauliCoMap fun | 0 => 2 | 1 => 0 | 2 => 1)).prod t)).add
((TensorTree.smul (-I) ((tensorNode
(basisVector pauliCoMap fun | 0 => 2 | 1 => 1 | 2 => 0)).prod t)).add
((TensorTree.smul (-1) ((tensorNode
(basisVector pauliCoMap fun | 0 => 3 | 1 => 0 | 2 => 0)).prod t)).add
((tensorNode
(basisVector pauliCoMap fun | 0 => 3 | 1 => 1 | 2 => 1)).prod
t))))))))).tensor := by
exact pauliCo_prod_basis_expand _
lemma pauliCo_contr_pauliContr_expand_aux :
{pauliCo | μ α β ⊗ pauliContr | μ α' β'}ᵀ.tensor
= ((tensorNode
((basisVector pauliMatrixContrPauliMatrixMap fun | 0 => 0 | 1 => 0 | 2 => 0 | 3 => 0) +
basisVector pauliMatrixContrPauliMatrixMap fun | 0 => 0 | 1 => 0 | 2 => 1 | 3 => 1)).add
((tensorNode
((basisVector pauliMatrixContrPauliMatrixMap fun | 0 => 1 | 1 => 1 | 2 => 0 | 3 => 0) +
basisVector pauliMatrixContrPauliMatrixMap fun | 0 => 1 | 1 => 1 | 2 => 1 | 3 => 1)).add
((TensorTree.smul (-1) (tensorNode
((basisVector pauliMatrixContrPauliMatrixMap fun | 0 => 0 | 1 => 1 | 2 => 0 | 3 => 1) +
basisVector pauliMatrixContrPauliMatrixMap fun | 0 => 0 | 1 => 1 | 2 => 1 | 3 => 0))).add
((TensorTree.smul (-1) (tensorNode
((basisVector pauliMatrixContrPauliMatrixMap fun | 0 => 1 | 1 => 0 | 2 => 0 | 3 => 1) +
basisVector pauliMatrixContrPauliMatrixMap fun | 0 => 1 | 1 => 0 | 2 => 1 | 3 => 0))).add
((TensorTree.smul I (tensorNode
((-I • basisVector pauliMatrixContrPauliMatrixMap fun | 0 => 0 | 1 => 1 | 2 => 0 | 3 => 1) +
I •
basisVector pauliMatrixContrPauliMatrixMap fun | 0 => 0 | 1 => 1 | 2 => 1 | 3 => 0))).add
((TensorTree.smul (-I) (tensorNode
((-I • basisVector pauliMatrixContrPauliMatrixMap fun | 0 => 1 | 1 => 0 | 2 => 0 | 3 => 1) +
I • basisVector pauliMatrixContrPauliMatrixMap fun | 0 => 1 | 1 => 0 | 2 => 1 | 3 => 0))).add
((TensorTree.smul (-1) (tensorNode
((basisVector pauliMatrixContrPauliMatrixMap fun | 0 => 0 | 1 => 0 | 2 => 0 | 3 => 0) +
(-1 : ) •
basisVector pauliMatrixContrPauliMatrixMap fun | 0 => 0 | 1 => 0 | 2 => 1 | 3 => 1))).add
(tensorNode
((basisVector pauliMatrixContrPauliMatrixMap fun | 0 => 1 | 1 => 1 | 2 => 0 | 3 => 0) +
(-1 : ) • basisVector pauliMatrixContrPauliMatrixMap
fun | 0 => 1 | 1 => 1 | 2 => 1 | 3 => 1))))))))).tensor := by
rw [contr_tensor_eq <| pauliCo_prod_basis_expand' _]
/- Moving contraction through addition. -/
rw [contr_add]
rw [add_tensor_eq_snd <| contr_add _ _]
rw [add_tensor_eq_snd <| add_tensor_eq_snd <| contr_add _ _]
rw [add_tensor_eq_snd <| add_tensor_eq_snd <| add_tensor_eq_snd <| contr_add _ _]
rw [add_tensor_eq_snd <| add_tensor_eq_snd <| add_tensor_eq_snd <| add_tensor_eq_snd <|
contr_add _ _]
rw [add_tensor_eq_snd <| add_tensor_eq_snd <| add_tensor_eq_snd <| add_tensor_eq_snd <|
add_tensor_eq_snd <| contr_add _ _]
rw [add_tensor_eq_snd <| add_tensor_eq_snd <| add_tensor_eq_snd <| add_tensor_eq_snd <|
add_tensor_eq_snd <| add_tensor_eq_snd <| contr_add _ _]
/- Moving contraction through smul. -/
rw [add_tensor_eq_snd <| add_tensor_eq_snd <| add_tensor_eq_fst <| contr_smul _ _]
rw [add_tensor_eq_snd <| add_tensor_eq_snd <| add_tensor_eq_snd <| add_tensor_eq_fst <|
contr_smul _ _]
rw [add_tensor_eq_snd <| add_tensor_eq_snd <| add_tensor_eq_snd <| add_tensor_eq_snd <|
add_tensor_eq_fst <| contr_smul _ _]
rw [add_tensor_eq_snd <| add_tensor_eq_snd <| add_tensor_eq_snd <| add_tensor_eq_snd <|
add_tensor_eq_snd <| add_tensor_eq_fst <| contr_smul _ _]
rw [add_tensor_eq_snd <| add_tensor_eq_snd <| add_tensor_eq_snd <| add_tensor_eq_snd <|
add_tensor_eq_snd <| add_tensor_eq_snd <| add_tensor_eq_fst <| contr_smul _ _]
/- Replacing the contractions. -/
rw [add_tensor_eq_fst <| eq_tensorNode_of_eq_tensor <| pauliMatrix_contr_lower_0_0_0]
rw [add_tensor_eq_snd <| add_tensor_eq_fst <| eq_tensorNode_of_eq_tensor <|
pauliMatrix_contr_lower_0_1_1]
rw [add_tensor_eq_snd <| add_tensor_eq_snd <| add_tensor_eq_fst <| smul_tensor_eq <|
eq_tensorNode_of_eq_tensor <| pauliMatrix_contr_lower_1_0_1]
rw [add_tensor_eq_snd <| add_tensor_eq_snd <| add_tensor_eq_snd <| add_tensor_eq_fst <|
smul_tensor_eq <| eq_tensorNode_of_eq_tensor <| pauliMatrix_contr_lower_1_1_0]
rw [add_tensor_eq_snd <| add_tensor_eq_snd <| add_tensor_eq_snd <| add_tensor_eq_snd <|
add_tensor_eq_fst <| smul_tensor_eq <| eq_tensorNode_of_eq_tensor <|
pauliMatrix_contr_lower_2_0_1]
rw [add_tensor_eq_snd <| add_tensor_eq_snd <| add_tensor_eq_snd <| add_tensor_eq_snd <|
add_tensor_eq_snd <| add_tensor_eq_fst <| smul_tensor_eq <| eq_tensorNode_of_eq_tensor
<| pauliMatrix_contr_lower_2_1_0]
rw [add_tensor_eq_snd <| add_tensor_eq_snd <| add_tensor_eq_snd <| add_tensor_eq_snd <|
add_tensor_eq_snd <| add_tensor_eq_snd <| add_tensor_eq_fst <| smul_tensor_eq <|
eq_tensorNode_of_eq_tensor <| pauliMatrix_contr_lower_3_0_0]
rw [add_tensor_eq_snd <| add_tensor_eq_snd <| add_tensor_eq_snd <| add_tensor_eq_snd <|
add_tensor_eq_snd <| add_tensor_eq_snd <| add_tensor_eq_snd <| eq_tensorNode_of_eq_tensor <|
pauliMatrix_contr_lower_3_1_1]
lemma pauliCo_contr_pauliContr_expand :
{pauliCo | ν α β ⊗ pauliContr | ν α' β'}ᵀ.tensor =
2 • basisVector pauliMatrixContrPauliMatrixMap (fun | 0 => 0 | 1 => 0 | 2 => 1 | 3 => 1)
+ 2 • basisVector pauliMatrixContrPauliMatrixMap (fun | 0 => 1 | 1 => 1 | 2 => 0 | 3 => 0)
- 2 • basisVector pauliMatrixContrPauliMatrixMap (fun | 0 => 0 | 1 => 1 | 2 => 1 | 3 => 0)
- 2 • basisVector pauliMatrixContrPauliMatrixMap (fun | 0 => 1 | 1 => 0 | 2 => 0 | 3 => 1) := by
rw [pauliCo_contr_pauliContr_expand_aux]
simp only [Nat.reduceAdd, Fin.isValue, Fin.succAbove_zero, neg_smul,
one_smul, add_tensor, tensorNode_tensor, smul_tensor, smul_add, smul_neg, _root_.smul_smul,
neg_mul, _root_.neg_neg]
ring_nf
rw [Complex.I_sq]
simp only [neg_smul, one_smul, _root_.neg_neg]
abel
/-- The statement that `η_{μν} σ^{μ α dot β} σ^{ν α' dot β'} = 2 ε^{αα'} ε^{dot β dot β'}`. -/
theorem pauliCo_contr_pauliContr :
{pauliCo | ν α β ⊗ pauliContr | ν α' β' = 2 •ₜ εL | α α' ⊗ εR | β β'}ᵀ := by
rw [pauliCo_contr_pauliContr_expand]
rw [perm_tensor_eq <| smul_tensor_eq <| leftMetric_mul_rightMetric_tree]
rw [perm_smul]
/- Moving perm through adds. -/
rw [smul_tensor_eq <| perm_add _ _ _]
rw [smul_tensor_eq <| add_tensor_eq_snd <| perm_add _ _ _]
rw [smul_tensor_eq <| add_tensor_eq_snd <| add_tensor_eq_snd <| perm_add _ _ _]
/- Moving perm through smul. -/
rw [smul_tensor_eq <| add_tensor_eq_snd <| add_tensor_eq_fst <| perm_smul _ _ _]
rw [smul_tensor_eq <| add_tensor_eq_snd <| add_tensor_eq_snd
<| add_tensor_eq_fst <| perm_smul _ _ _]
/- Perm acting on basis. -/
erw [smul_tensor_eq <| add_tensor_eq_fst <| perm_basisVector_tree _ _]
erw [smul_tensor_eq <| add_tensor_eq_snd <| add_tensor_eq_fst <| smul_tensor_eq <|
perm_basisVector_tree _ _]
erw [smul_tensor_eq <| add_tensor_eq_snd <| add_tensor_eq_snd <| add_tensor_eq_fst <|
smul_tensor_eq <| perm_basisVector_tree _ _]
erw [smul_tensor_eq <| add_tensor_eq_snd <| add_tensor_eq_snd <| add_tensor_eq_snd <|
perm_basisVector_tree _ _]
/- Simplifying. -/
simp only [smul_tensor, add_tensor, tensorNode_tensor]
have h1 (b0011 b1100 b0110 b1001 : CoeSort.coe (complexLorentzTensor.F.obj
(OverColor.mk pauliMatrixContrPauliMatrixMap))) :
((2 • b0011 + 2 • b1100) - 2 • b0110 - 2 • b1001) = (2 : ) • ((b0011) +
(((-1 : )• b0110) + (((-1 : ) •b1001) + b1100))) := by
trans (2 : ) • b0011 + (2 : ) • b1100 - ((2 : ) • b0110) - ((2 : ) • b1001)
· repeat rw [two_smul]
· simp only [neg_smul, one_smul, smul_add, smul_neg]
abel
rw [h1]
congr
· funext i
fin_cases i <;> rfl
· funext i
fin_cases i <;> rfl
· funext i
fin_cases i <;> rfl
· funext i
fin_cases i <;> rfl
end complexLorentzTensor