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Physlib.Relativity.Tensors.ComplexTensor.Weyl.Two

Tensor product of two Weyl fermion

Equivalences to matrices.

Group actions

The symm version of the group actions.

42 declarations

definition

Linear equivalence (L⊗L).V≅Mat2×2(C)(L \otimes L).V \cong \text{Mat}_{2 \times 2}(\mathbb{C})

This definition establishes a C\mathbb{C}-linear isomorphism between the vector space of the tensor product of two left-handed Weyl fermions, (L⊗L).V(L \otimes L).V, and the space of 2×22 \times 2 complex matrices, Mat2×2(C)\text{Mat}_{2 \times 2}(\mathbb{C}). The equivalence is constructed by mapping the tensor product of the standard bases for each left-handed fermion space to the corresponding entries of a 2×22 \times 2 matrix.

theorem

Expansion of leftLeftToMatrix.symm(M)\text{leftLeftToMatrix.symm}(M) in the standard basis ei⊗eje_i \otimes e_j

For any 2×22 \times 2 complex matrix M∈Mat2×2(C)M \in \text{Mat}_{2 \times 2}(\mathbb{C}), the inverse of the linear isomorphism leftLeftToMatrix\text{leftLeftToMatrix} (which identifies the vector space of the tensor product of two left-handed Weyl fermions (L⊗L).V(L \otimes L).V with 2×22 \times 2 matrices) maps MM to: leftLeftToMatrix.symm(M)=∑i,j∈{0,1}Mij(ei⊗ej)\text{leftLeftToMatrix.symm}(M) = \sum_{i, j \in \{0, 1\}} M_{ij} (e_i \otimes e_j) where eie_i and eje_j denote the standard basis vectors (`leftBasis`) of the left-handed Weyl fermion vector space, MijM_{ij} represents the entry of the matrix MM at row ii and column jj, and ⊗\otimes denotes the tensor product over C\mathbb{C}.

definition

Linear equivalence (VL′⊗VL′)≅Mat2×2(C)(V_{L'} \otimes V_{L'}) \cong \text{Mat}_{2 \times 2}(\mathbb{C})

This definition establishes a linear equivalence (isomorphism) between the vector space of the tensor product of two alternative left-handed Weyl fermions, denoted VL′⊗VL′V_{L'} \otimes V_{L'}, and the space of 2×22 \times 2 complex matrices Mat2×2(C)\text{Mat}_{2 \times 2}(\mathbb{C}). The equivalence is constructed by mapping the tensor product basis (formed by `altLeftBasis`) to the standard matrix basis.

theorem

Expansion of altLeftaltLeftToMatrix−1\text{altLeftaltLeftToMatrix}^{-1} in terms of the alternative left-handed basis tensors

For any 2×22 \times 2 complex matrix M∈Mat2×2(C)M \in \text{Mat}_{2 \times 2}(\mathbb{C}), the image of MM under the inverse of the linear equivalence `altLeftaltLeftToMatrix` is given by the sum altLeftaltLeftToMatrix−1(M)=∑i=01∑j=01Mij(ei′⊗ej′) \text{altLeftaltLeftToMatrix}^{-1}(M) = \sum_{i=0}^1 \sum_{j=0}^1 M_{ij} (e'_i \otimes e'_j) where MijM_{ij} are the entries of the matrix MM, and ek′e'_k denotes the kk-th basis vector of the alternative left-handed Weyl fermion space (represented by `altLeftBasis`).

definition

Linear isomorphism (VL⊗VL~)≅M2×2(C)(V_L \otimes V_{\tilde{L}}) \cong M_{2 \times 2}(\mathbb{C})

This definition establishes a linear isomorphism between the vector space associated with the tensor product of a left-handed Weyl fermion VLV_L and an alternate left-handed Weyl fermion VL~V_{\tilde{L}} and the space of 2×22 \times 2 complex matrices M2×2(C)M_{2 \times 2}(\mathbb{C}). Specifically, for a tensor expressed in the basis {ei⊗fj}i,j∈{0,1}\{e_i \otimes f_j\}_{i,j \in \{0,1\}}, where {ei}\{e_i\} is the standard basis for the left-handed spinors (`leftBasis`) and {fj}\{f_j\} is the standard basis for the alternate left-handed spinors (`altLeftBasis`), the map identifies the tensor with a matrix whose (i,j)(i, j)-th entry is the coefficient of the basis element ei⊗fje_i \otimes f_j.

theorem

leftAltLeftToMatrix−1(M)=∑i,jMij(ei⊗fj)\text{leftAltLeftToMatrix}^{-1}(M) = \sum_{i,j} M_{ij} (e_i \otimes f_j)

For any 2×22 \times 2 complex matrix M∈M2×2(C)M \in M_{2 \times 2}(\mathbb{C}), the inverse of the linear isomorphism leftAltLeftToMatrix:(VL⊗VL~)≅M2×2(C)\text{leftAltLeftToMatrix} : (V_L \otimes V_{\tilde{L}}) \cong M_{2 \times 2}(\mathbb{C}) maps MM to the tensor sum leftAltLeftToMatrix−1(M)=∑i,j∈{0,1}Mij(ei⊗fj)\text{leftAltLeftToMatrix}^{-1}(M) = \sum_{i, j \in \{0, 1\}} M_{ij} (e_i \otimes f_j) where {ei}\{e_i\} is the standard basis for the left-handed Weyl spinor space VLV_L (`leftBasis`) and {fj}\{f_j\} is the standard basis for the alternate left-handed Weyl spinor space VL~V_{\tilde{L}} (`altLeftBasis`).

definition

Complex linear equivalence between (ValtL⊗VL)(V_{\text{altL}} \otimes V_{\text{L}}) and 2×22 \times 2 complex matrices

The definition `altLeftLeftToMatrix` provides a C\mathbb{C}-linear equivalence between the vector space of the tensor product of an alternative left-handed Weyl fermion and a left-handed Weyl fermion, denoted (altLeftHanded⊗leftHanded).V(altLeftHanded \otimes leftHanded).V, and the space of 2×22 \times 2 complex matrices M2×2(C)M_{2 \times 2}(\mathbb{C}). Under this equivalence, a matrix MM corresponds to the tensor ∑i,jMij(ei′⊗ej)\sum_{i,j} M_{ij} (e'_i \otimes e_j), where {ei′}\{e'_i\} and {ej}\{e_j\} are the standard bases for the alternative left-handed and left-handed fermion spaces, respectively.

theorem

Expansion of altLeftLeftToMatrix−1(M)\text{altLeftLeftToMatrix}^{-1}(M) in the standard basis as ∑i,jMij(ei′⊗ej)\sum_{i,j} M_{ij} (e'_i \otimes e_j)

Let M∈M2×2(C)M \in M_{2 \times 2}(\mathbb{C}) be a 2×22 \times 2 complex matrix. The inverse of the C\mathbb{C}-linear equivalence `altLeftLeftToMatrix` maps MM to a tensor in the product space of an alternative left-handed Weyl fermion and a left-handed Weyl fermion, expressed in the standard bases as: altLeftLeftToMatrix−1(M)=∑i,jMij(ei′⊗ej)\text{altLeftLeftToMatrix}^{-1}(M) = \sum_{i,j} M_{ij} (e'_i \otimes e_j) where {ei′}i∈{0,1}\{e'_i\}_{i \in \{0,1\}} is the standard basis for the alternative left-handed fermion space (`altLeftBasis`) and {ej}j∈{0,1}\{e_j\}_{j \in \{0,1\}} is the standard basis for the left-handed fermion space (`leftBasis`).

definition

Complex linear equivalence between the tensor product of two right-handed Weyl fermions and 2×22 \times 2 complex matrices

The complex linear equivalence between the vector space of the tensor product of two right-handed Weyl fermions and the space of 2×22 \times 2 complex matrices.

theorem

rightRightToMatrix−1(M)=∑i,jMij(bi⊗bj)\text{rightRightToMatrix}^{-1}(M) = \sum_{i, j} M_{ij} (b_i \otimes b_j)

For any 2×22 \times 2 complex matrix M∈M2×2(C)M \in M_{2 \times 2}(\mathbb{C}), the inverse of the linear equivalence `rightRightToMatrix` (which maps the tensor product of two right-handed Weyl fermions to matrices) maps MM back to the tensor product space according to the expansion: rightRightToMatrix−1(M)=∑i,j∈{0,1}Mij(bi⊗bj)\text{rightRightToMatrix}^{-1}(M) = \sum_{i, j \in \{0, 1\}} M_{ij} (b_i \otimes b_j) where MijM_{ij} represents the entry of the matrix MM at row ii and column jj, and bkb_k represents the kk-th element of the standard basis for right-handed Weyl fermions (`rightBasis`).

definition

Complex linear equivalence (ValtRight⊗ValtRight)≃M2×2(C)(V_{\text{altRight}} \otimes V_{\text{altRight}}) \simeq M_{2 \times 2}(\mathbb{C})

The complex linear equivalence between the vector space of the tensor product of two alternative right-handed Weyl fermions and the space of 2×22 \times 2 complex matrices M2×2(C)M_{2 \times 2}(\mathbb{C}). This equivalence is established by representing elements of the tensor product in the basis formed by the tensor product of `altRightBasis` with itself.

theorem

altRightAltRightToMatrix−1(M)=∑i,jMij(e~i⊗e~j)\text{altRightAltRightToMatrix}^{-1}(M) = \sum_{i, j} M_{ij} (\tilde{e}_i \otimes \tilde{e}_j)

For any 2×22 \times 2 complex matrix M∈M2×2(C)M \in M_{2 \times 2}(\mathbb{C}), the inverse of the linear equivalence altRightAltRightToMatrix\text{altRightAltRightToMatrix} (which maps the tensor product of alternative right-handed Weyl fermions to matrices) can be expanded as: altRightAltRightToMatrix−1(M)=∑i,j∈{0,1}Mij(e~i⊗e~j)\text{altRightAltRightToMatrix}^{-1}(M) = \sum_{i, j \in \{0, 1\}} M_{ij} (\tilde{e}_i \otimes \tilde{e}_j) where e~k\tilde{e}_k denotes the kk-th element of the standard basis for the alternative right-handed Weyl fermion space (`altRightBasis`).

definition

Linear equivalence (rightHanded⊗altRightHanded).V≅Mat2×2(C)(rightHanded \otimes altRightHanded).V \cong \text{Mat}_{2 \times 2}(\mathbb{C})

This definition establishes a C\mathbb{C}-linear equivalence between the vector space of the tensor product of a right-handed Weyl fermion and an alternative right-handed Weyl fermion, denoted as (VR⊗ValtR)(V_R \otimes V_{\text{alt}R}), and the space of 2×22 \times 2 complex matrices, Mat2×2(C)\text{Mat}_{2 \times 2}(\mathbb{C}). The isomorphism is defined by mapping the tensor product of the canonical bases {ei⊗e~j}\{e_i \otimes \tilde{e}_j\} to the corresponding matrix entries MijM_{ij}.

theorem

Basis Expansion of the Inverse Matrix Equivalence for VR⊗ValtRV_R \otimes V_{\text{alt}R}

For any 2×22 \times 2 complex matrix M∈Mat2×2(C)M \in \text{Mat}_{2 \times 2}(\mathbb{C}), the inverse of the linear equivalence rightAltRightToMatrix\text{rightAltRightToMatrix} (which maps elements of the tensor product space VR⊗ValtRV_R \otimes V_{\text{alt}R} to matrices) maps MM back to its representation in the tensor product basis: rightAltRightToMatrix−1(M)=∑i,j∈{0,1}Mij(ei⊗e~j)\text{rightAltRightToMatrix}^{-1}(M) = \sum_{i, j \in \{0, 1\}} M_{ij} (e_i \otimes \tilde{e}_j) where {ei}\{e_i\} is the standard basis for the right-handed Weyl fermion space (`rightBasis`) and {e~j}\{\tilde{e}_j\} is the standard basis for the alternative right-handed Weyl fermion space (`altRightBasis`).

definition

Linear equivalence (altRightHanded⊗rightHanded).V≅M2×2(C)(\text{altRightHanded} \otimes \text{rightHanded}).V \cong M_{2 \times 2}(\mathbb{C})

The linear equivalence `altRightRightToMatrix` is an isomorphism between the vector space VV associated with the tensor product of an alternate right-handed Weyl fermion and a right-handed Weyl fermion, denoted as (altRightHanded⊗rightHanded).V(\text{altRightHanded} \otimes \text{rightHanded}).V, and the space of 2×22 \times 2 complex matrices M2×2(C)M_{2 \times 2}(\mathbb{C}). This isomorphism is constructed by mapping the tensor product basis {ei⊗fj}\{e_i \otimes f_j\}—where eie_i is the ii-th basis vector of the alternate right-handed fermion space (`altRightBasis`) and fjf_j is the jj-th basis vector of the right-handed fermion space (`rightBasis`)—to the corresponding matrix components MijM_{ij}.

theorem

Expansion of altRightRightToMatrix−1(M)\text{altRightRightToMatrix}^{-1}(M) in the basis ei⊗fje_i \otimes f_j

For any 2×22 \times 2 complex matrix M∈M2×2(C)M \in M_{2 \times 2}(\mathbb{C}), the inverse of the linear isomorphism `altRightRightToMatrix` maps MM back to the tensor product space of an alternate right-handed and a right-handed Weyl fermion according to the formula: altRightRightToMatrix−1(M)=∑i,j∈{0,1}Mij⋅(ei⊗fj)\text{altRightRightToMatrix}^{-1}(M) = \sum_{i, j \in \{0, 1\}} M_{ij} \cdot (e_i \otimes f_j) where eie_i are the basis vectors of the alternate right-handed Weyl fermion space (`altRightBasis`) and fjf_j are the basis vectors of the right-handed Weyl fermion space (`rightBasis`).

definition

Linear equivalence (altLeftHanded⊗altRightHanded).V≃Mat2×2(C)(\text{altLeftHanded} \otimes \text{altRightHanded}).V \simeq \text{Mat}_{2 \times 2}(\mathbb{C})

This is a C\mathbb{C}-linear equivalence between the vector space VV of the tensor product of an alternating left-handed Weyl fermion and an alternating right-handed Weyl fermion, denoted by (altLeftHanded⊗altRightHanded).V(\text{altLeftHanded} \otimes \text{altRightHanded}).V, and the space of 2×22 \times 2 matrices over the complex numbers, Mat2×2(C)\text{Mat}_{2 \times 2}(\mathbb{C}).

theorem

Expansion of altLeftAltRightToMatrix−1M\text{altLeftAltRightToMatrix}^{-1} M in the standard tensor basis

For any 2×22 \times 2 complex matrix M∈Mat2×2(C)M \in \text{Mat}_{2 \times 2}(\mathbb{C}), the inverse of the linear equivalence between the tensor product of alternating left-handed and right-handed Weyl fermions and 2×22 \times 2 matrices, denoted altLeftAltRightToMatrix−1\text{altLeftAltRightToMatrix}^{-1}, maps MM to the sum: altLeftAltRightToMatrix−1(M)=∑i,jMij(eiL⊗ejR)\text{altLeftAltRightToMatrix}^{-1}(M) = \sum_{i, j} M_{ij} (e^L_i \otimes e^R_j) where MijM_{ij} are the entries of the matrix MM, eiLe^L_i are the basis elements of the alternating left-handed Weyl fermion space (`altLeftBasis`), and ejRe^R_j are the basis elements of the alternating right-handed Weyl fermion space (`altRightBasis`).

definition

Linear equivalence VL⊗VR≅Mat2×2(C)V_L \otimes V_R \cong \text{Mat}_{2 \times 2}(\mathbb{C})

This definition provides a C\mathbb{C}-linear equivalence between the tensor product of the vector spaces associated with left-handed and right-handed Weyl fermions, denoted VL⊗VRV_L \otimes V_R, and the space of 2×22 \times 2 complex matrices Mat2×2(C)\text{Mat}_{2 \times 2}(\mathbb{C}).

theorem

leftRightToMatrix−1(M)=∑i,jMij(eiL⊗ejR)\text{leftRightToMatrix}^{-1}(M) = \sum_{i, j} M_{ij} (e^L_i \otimes e^R_j)

Let VLV_L and VRV_R be the vector spaces associated with left-handed and right-handed Weyl fermions, respectively, and let {eiL}\{e^L_i\} and {ejR}\{e^R_j\} be their standard bases. Let Φ:VL⊗VR≅Mat2×2(C)\Phi : V_L \otimes V_R \cong \text{Mat}_{2 \times 2}(\mathbb{C}) be the linear equivalence `leftRightToMatrix`. For any 2×22 \times 2 complex matrix MM, the inverse mapping Φ−1\Phi^{-1} (denoted as `leftRightToMatrix.symm`) is given by: Φ−1(M)=∑i,j∈{0,1}Mij(eiL⊗ejR)\Phi^{-1}(M) = \sum_{i, j \in \{0, 1\}} M_{ij} (e^L_i \otimes e^R_j) where MijM_{ij} are the entries of the matrix MM, and ⊗\otimes denotes the tensor product over C\mathbb{C}.

theorem

The SL(2,C)SL(2, \mathbb{C}) action on L⊗LL \otimes L is Φ(M⋅v)=MΦ(v)M⊺\Phi(M \cdot v) = M \Phi(v) M^\intercal

Let LL denote the vector space of left-handed Weyl fermions. Let Φ:L⊗L→≅Mat2×2(C)\Phi: L \otimes L \xrightarrow{\cong} \text{Mat}_{2 \times 2}(\mathbb{C}) be the C\mathbb{C}-linear isomorphism (defined as `leftLeftToMatrix`) that maps the tensor product of two left-handed fermions to the space of 2×22 \times 2 complex matrices. For any vector v∈L⊗Lv \in L \otimes L and any transformation M∈SL(2,C)M \in SL(2, \mathbb{C}), the action of MM on the tensor product space, given by the induced representation ρ(M)⊗ρ(M)\rho(M) \otimes \rho(M), is equivalent to the matrix transformation: Φ((ρ(M)⊗ρ(M))v)=MΦ(v)M⊺\Phi((\rho(M) \otimes \rho(M)) v) = M \Phi(v) M^\intercal where MM is the matrix representation of the group element and M⊺M^\intercal is its transpose.

theorem

SL(2,C)SL(2, \mathbb{C}) action on VL′⊗VL′V_{L'} \otimes V_{L'} is Φ(v)↦(M−1)TΦ(v)M−1\Phi(v) \mapsto (M^{-1})^T \Phi(v) M^{-1}

Let VL′V_{L'} denote the vector space of alternative left-handed Weyl fermions. For any element v∈VL′⊗VL′v \in V_{L'} \otimes V_{L'} in the tensor product space and any matrix M∈SL(2,C)M \in SL(2, \mathbb{C}), the action of MM on vv (defined by the tensor product of the representations ρ(M)⊗ρ(M)\rho(M) \otimes \rho(M)) corresponds to the following matrix transformation: Φ((ρ(M)⊗ρ(M))v)=(M−1)TΦ(v)M−1\Phi((\rho(M) \otimes \rho(M)) v) = (M^{-1})^T \Phi(v) M^{-1} where Φ:VL′⊗VL′→Mat2×2(C)\Phi: V_{L'} \otimes V_{L'} \to \text{Mat}_{2 \times 2}(\mathbb{C}) is the linear isomorphism `altLeftaltLeftToMatrix`, and M−1M^{-1} and MTM^T denote the matrix inverse and transpose of MM, respectively.

theorem

The SL(2,C)SL(2, \mathbb{C}) action on VL⊗VL~V_L \otimes V_{\tilde{L}} is equivalent to matrix conjugation.

Let VLV_L and VL~V_{\tilde{L}} be the vector spaces associated with left-handed Weyl spinors and alternate left-handed Weyl spinors, respectively. Let Φ:VL⊗VL~→M2×2(C)\Phi: V_L \otimes V_{\tilde{L}} \to M_{2 \times 2}(\mathbb{C}) be the linear isomorphism `leftAltLeftToMatrix` which maps a tensor vv to a 2×22 \times 2 complex matrix. For any group element M∈SL(2,C)M \in SL(2, \mathbb{C}) and any tensor v∈VL⊗VL~v \in V_L \otimes V_{\tilde{L}}, the representation of SL(2,C)SL(2, \mathbb{C}) on the tensor product space satisfies: Φ((ρL(M)⊗ρL~(M))v)=MΦ(v)M−1\Phi((\rho_L(M) \otimes \rho_{\tilde{L}}(M))v) = M \Phi(v) M^{-1} where ρL\rho_L and ρL~\rho_{\tilde{L}} are the group representations on VLV_L and VL~V_{\tilde{L}}, and MM is the matrix representation of the group element.

theorem

SL(2,C)SL(2, \mathbb{C}) action on ValtL⊗VLV_{\text{altL}} \otimes V_{\text{L}} is equivalent to (M−1)T⋅X⋅MT(M^{-1})^T \cdot X \cdot M^T

Let ValtLV_{\text{altL}} and VLV_{\text{L}} be the vector spaces associated with the alternative left-handed and left-handed Weyl fermion representations, respectively. Let ρaltL\rho_{\text{altL}} and ρL\rho_{\text{L}} be the corresponding representations of SL(2,C)SL(2, \mathbb{C}) on these spaces. For any element v∈ValtL⊗VLv \in V_{\text{altL}} \otimes V_{\text{L}} and any group element M∈SL(2,C)M \in SL(2, \mathbb{C}), the C\mathbb{C}-linear equivalence f:ValtL⊗VL→M2×2(C)f: V_{\text{altL}} \otimes V_{\text{L}} \to M_{2 \times 2}(\mathbb{C}) (defined by `altLeftLeftToMatrix`) satisfies: f((ρaltL(M)⊗ρL(M))v)=(M−1)Tf(v)MTf((\rho_{\text{altL}}(M) \otimes \rho_{\text{L}}(M))v) = (M^{-1})^T f(v) M^T where M−1M^{-1} is the matrix inverse and MTM^T is the matrix transpose of the matrix representation of MM.

theorem

The SL(2,C)SL(2, \mathbb{C}) action on rightHanded⊗rightHanded\text{rightHanded} \otimes \text{rightHanded} is MˉΦ(v)MˉT\bar{M} \Phi(v) \bar{M}^{\text{T}}

Let VR⊗VRV_R \otimes V_R be the vector space of the tensor product of two right-handed Weyl fermions. Let Φ:VR⊗VR≅Mat(2,C)\Phi : V_R \otimes V_R \cong \text{Mat}(2, \mathbb{C}) be the complex linear equivalence `rightRightToMatrix` that maps a tensor to a 2×22 \times 2 complex matrix. For any tensor v∈VR⊗VRv \in V_R \otimes V_R and any group element M∈SL(2,C)M \in SL(2, \mathbb{C}), the action of MM on the tensor product, denoted by ρ(M)⊗ρ(M)\rho(M) \otimes \rho(M), satisfies the identity: Φ((ρ(M)⊗ρ(M))v)=MˉΦ(v)MˉT\Phi((\rho(M) \otimes \rho(M)) v) = \bar{M} \Phi(v) \bar{M}^{\text{T}} where Mˉ\bar{M} is the complex conjugate of the matrix MM and MˉT\bar{M}^{\text{T}} is its transpose.

theorem

The SL(2,C)SL(2, \mathbb{C}) action on ValtRight⊗ValtRightV_{\text{altRight}} \otimes V_{\text{altRight}} corresponds to matrix multiplication by (M−1)†(M^{-1})^\dagger and its transpose.

Let ValtRightV_{\text{altRight}} be the vector space associated with alternative right-handed Weyl fermions, and let ρ\rho be the representation of SL(2,C)SL(2, \mathbb{C}) on ValtRightV_{\text{altRight}}. Let Φ:ValtRight⊗ValtRight→≅M2×2(C)\Phi : V_{\text{altRight}} \otimes V_{\text{altRight}} \xrightarrow{\cong} M_{2 \times 2}(\mathbb{C}) be the complex linear equivalence that maps an element of the tensor product to its corresponding 2×22 \times 2 complex matrix representation. For any vector v∈ValtRight⊗ValtRightv \in V_{\text{altRight}} \otimes V_{\text{altRight}} and any matrix M∈SL(2,C)M \in SL(2, \mathbb{C}), the matrix representation of the transformed vector under the induced group action is given by: Φ((ρ(M)⊗ρ(M))v)=(M−1)†Φ(v)((M−1)†)T\Phi((\rho(M) \otimes \rho(M)) v) = (M^{-1})^\dagger \Phi(v) ((M^{-1})^\dagger)^T where (M−1)†(M^{-1})^\dagger denotes the conjugate transpose of the inverse of MM, and TT denotes the transpose.

theorem

SL(2,C)SL(2, \mathbb{C}) action on VR⊗ValtRV_R \otimes V_{\text{alt}R} as matrix transformation

Let VRV_R be the vector space of right-handed Weyl fermions and ValtRV_{\text{alt}R} be the vector space of alternative right-handed Weyl fermions. Let Φ:VR⊗ValtR≅Mat2×2(C)\Phi: V_R \otimes V_{\text{alt}R} \cong \text{Mat}_{2 \times 2}(\mathbb{C}) be the C\mathbb{C}-linear equivalence that maps the tensor product of these spaces to 2×22 \times 2 complex matrices. For any vector v∈VR⊗ValtRv \in V_R \otimes V_{\text{alt}R} and any matrix M∈SL(2,C)M \in SL(2, \mathbb{C}), the group action of SL(2,C)SL(2, \mathbb{C}) on the tensor product is given by: Φ((ρR(M)⊗ρaltR(M))v)=Mˉ⋅Φ(v)⋅((M−1)†)T\Phi\left( (\rho_R(M) \otimes \rho_{\text{alt}R}(M)) v \right) = \bar{M} \cdot \Phi(v) \cdot ((M^{-1})^\dagger)^T where ρR\rho_R and ρaltR\rho_{\text{alt}R} are the representations of SL(2,C)SL(2, \mathbb{C}) on VRV_R and ValtRV_{\text{alt}R} respectively, Mˉ\bar{M} denotes the entry-wise complex conjugate of MM, M−1M^{-1} is the matrix inverse, and †\dagger and TT denote the conjugate transpose and transpose operations.

theorem

SL(2,C)SL(2, \mathbb{C}) action on altRightHanded⊗rightHanded\text{altRightHanded} \otimes \text{rightHanded} equivalent to matrix multiplication by (M−1)†(M^{-1})^\dagger and M‾⊤\overline{M}^\top

Let VV be the vector space associated with the tensor product of an alternate right-handed Weyl fermion and a right-handed Weyl fermion, denoted as altRightHanded⊗rightHanded\text{altRightHanded} \otimes \text{rightHanded}. Let Φ:V→M2×2(C)\Phi: V \to M_{2 \times 2}(\mathbb{C}) be the linear isomorphism `altRightRightToMatrix`. For any M∈SL(2,C)M \in SL(2, \mathbb{C}) and any v∈Vv \in V, the group action of SL(2,C)SL(2, \mathbb{C}) on vv through the tensor product of representations ρaltRight⊗ρright\rho_{\text{altRight}} \otimes \rho_{\text{right}} corresponds to the matrix transformation: Φ((ρaltRight(M)⊗ρright(M))v)=(M−1)†Φ(v)M‾⊤\Phi((\rho_{\text{altRight}}(M) \otimes \rho_{\text{right}}(M)) v) = (M^{-1})^\dagger \Phi(v) \overline{M}^\top where (M−1)†(M^{-1})^\dagger denotes the conjugate transpose of the inverse of MM, and M‾⊤\overline{M}^\top denotes the transpose of the complex conjugate of MM.

theorem

SL(2,C)SL(2, \mathbb{C}) action on altLeftHanded⊗altRightHanded\text{altLeftHanded} \otimes \text{altRightHanded} via Φ(ρ(M)v)=(M−1)TΦ(v)M−1‾\Phi(\rho(M)v) = (M^{-1})^T \Phi(v) \overline{M^{-1}}

Let VV be the vector space corresponding to the tensor product of an alternating left-handed Weyl fermion and an alternating right-handed Weyl fermion, denoted by (altLeftHanded⊗altRightHanded).V(\text{altLeftHanded} \otimes \text{altRightHanded}).V. Let Φ:V→Mat2×2(C)\Phi: V \to \text{Mat}_{2 \times 2}(\mathbb{C}) be the C\mathbb{C}-linear equivalence `altLeftAltRightToMatrix` which maps vectors in this space to 2×22 \times 2 complex matrices. For any vector v∈Vv \in V and any group element M∈SL(2,C)M \in SL(2, \mathbb{C}), the action of MM on vv through the representation ρ\rho satisfies: Φ(ρ(M)v)=(M−1)TΦ(v)M−1‾ \Phi(\rho(M)v) = (M^{-1})^T \Phi(v) \overline{M^{-1}} where (M−1)T(M^{-1})^T is the transpose of the inverse of MM, and M−1‾\overline{M^{-1}} is the complex conjugate of the inverse of MM.

theorem

The SL(2,C)SL(2, \mathbb{C}) action on VL⊗VRV_L \otimes V_R corresponds to matrix transformation by MAM†M A M^\dagger

Let VLV_L and VRV_R be the vector spaces associated with left-handed and right-handed Weyl fermions, respectively. Let ϕ:VL⊗VR≅Mat2×2(C)\phi : V_L \otimes V_R \cong \text{Mat}_{2 \times 2}(\mathbb{C}) be the linear equivalence `leftRightToMatrix`. For any tensor v∈VL⊗VRv \in V_L \otimes V_R and any matrix M∈SL(2,C)M \in SL(2, \mathbb{C}), the action of the group on the tensor product satisfies: ϕ((ρL(M)⊗ρR(M))v)=Mϕ(v)M†\phi\left( (\rho_L(M) \otimes \rho_R(M)) v \right) = M \phi(v) M^\dagger where ρL(M)\rho_L(M) and ρR(M)\rho_R(M) are the representations of SL(2,C)SL(2, \mathbb{C}) on VLV_L and VRV_R respectively, and M†M^\dagger denotes the conjugate transpose (Hermitian conjugate) of the matrix MM.

theorem

The SL(2,C)SL(2, \mathbb{C}) action on L⊗LL \otimes L via Φ−1\Phi^{-1} is (ρ⊗ρ)Φ−1(v)=Φ−1(MvM⊺)(\rho \otimes \rho) \Phi^{-1}(v) = \Phi^{-1}(M v M^\intercal)

Let LL be the vector space of left-handed Weyl fermions. Let Φ:L⊗L≅Mat2×2(C)\Phi: L \otimes L \cong \text{Mat}_{2 \times 2}(\mathbb{C}) be the C\mathbb{C}-linear isomorphism (defined as `leftLeftToMatrix`) that identifies the tensor product of two left-handed fermions with the space of 2×22 \times 2 complex matrices. For any matrix v∈Mat2×2(C)v \in \text{Mat}_{2 \times 2}(\mathbb{C}) and any transformation M∈SL(2,C)M \in SL(2, \mathbb{C}), the induced representation ρL(M)⊗ρL(M)\rho_L(M) \otimes \rho_L(M) acting on the tensor Φ−1(v)\Phi^{-1}(v) satisfies: (ρL(M)⊗ρL(M))(Φ−1(v))=Φ−1(MvM⊺)(\rho_L(M) \otimes \rho_L(M))(\Phi^{-1}(v)) = \Phi^{-1}(M v M^\intercal) where Φ−1\Phi^{-1} is the inverse isomorphism `leftLeftToMatrix.symm`, ρL(M)\rho_L(M) is the representation of SL(2,C)SL(2, \mathbb{C}) on LL, and M⊺M^\intercal denotes the transpose of the matrix MM.

theorem

The SL(2,C)SL(2, \mathbb{C}) action on VL′⊗VL′V_{L'} \otimes V_{L'} via Φ−1\Phi^{-1} is equivalent to v↦(M−1)TvM−1v \mapsto (M^{-1})^T v M^{-1}

Let VL′V_{L'} be the vector space of alternative left-handed Weyl fermions. Let Φ:VL′⊗VL′→Mat2×2(C)\Phi: V_{L'} \otimes V_{L'} \to \text{Mat}_{2 \times 2}(\mathbb{C}) be the C\mathbb{C}-linear isomorphism `altLeftaltLeftToMatrix` that identifies the tensor product with the space of 2×22 \times 2 complex matrices. For any matrix v∈Mat2×2(C)v \in \text{Mat}_{2 \times 2}(\mathbb{C}) and any transformation M∈SL(2,C)M \in SL(2, \mathbb{C}), the induced representation ρL′(M)⊗ρL′(M)\rho_{L'}(M) \otimes \rho_{L'}(M) acting on the tensor Φ−1(v)\Phi^{-1}(v) satisfies: (ρL′(M)⊗ρL′(M))(Φ−1(v))=Φ−1((M−1)TvM−1)(\rho_{L'}(M) \otimes \rho_{L'}(M))(\Phi^{-1}(v)) = \Phi^{-1}((M^{-1})^T v M^{-1}) where Φ−1\Phi^{-1} is the inverse isomorphism `altLeftaltLeftToMatrix.symm`, ρL′\rho_{L'} is the representation of SL(2,C)SL(2, \mathbb{C}) on VL′V_{L'}, and (M−1)T(M^{-1})^T denotes the transpose of the inverse matrix of MM.

theorem

The SL(2,C)SL(2, \mathbb{C}) action on VL⊗VL~V_L \otimes V_{\tilde{L}} via Φ−1\Phi^{-1} is equivalent to matrix conjugation.

Let VLV_L and VL~V_{\tilde{L}} be the vector spaces associated with left-handed Weyl spinors and alternate left-handed Weyl spinors, respectively. Let Φ:VL⊗VL~→M2×2(C)\Phi: V_L \otimes V_{\tilde{L}} \to M_{2 \times 2}(\mathbb{C}) be the linear isomorphism `leftAltLeftToMatrix` that identifies a tensor with a 2×22 \times 2 complex matrix. For any matrix v∈M2×2(C)v \in M_{2 \times 2}(\mathbb{C}) and any group element M∈SL(2,C)M \in SL(2, \mathbb{C}), the representation of SL(2,C)SL(2, \mathbb{C}) on the tensor product space satisfies: (ρL(M)⊗ρL~(M))(Φ−1(v))=Φ−1(MvM−1)(\rho_L(M) \otimes \rho_{\tilde{L}}(M))(\Phi^{-1}(v)) = \Phi^{-1}(M v M^{-1}) where Φ−1\Phi^{-1} is the inverse isomorphism (`leftAltLeftToMatrix.symm`), and ρL\rho_L and ρL~\rho_{\tilde{L}} are the group representations on VLV_L and VL~V_{\tilde{L}}.

theorem

The SL(2,C)SL(2, \mathbb{C}) action on ValtL⊗VLV_{\text{altL}} \otimes V_{\text{L}} via Φ−1\Phi^{-1} is equivalent to v↦(M−1)TvMTv \mapsto (M^{-1})^T v M^T

Let ValtLV_{\text{altL}} and VLV_{\text{L}} be the vector spaces associated with the alternative left-handed and left-handed Weyl fermion representations, respectively. Let Φ:ValtL⊗VL→M2×2(C)\Phi: V_{\text{altL}} \otimes V_{\text{L}} \to M_{2 \times 2}(\mathbb{C}) be the complex linear equivalence `altLeftLeftToMatrix`. For any matrix v∈M2×2(C)v \in M_{2 \times 2}(\mathbb{C}) and any group element M∈SL(2,C)M \in SL(2, \mathbb{C}), the representation of SL(2,C)SL(2, \mathbb{C}) on the tensor product space satisfies: (ρaltL(M)⊗ρL(M))(Φ−1(v))=Φ−1((M−1)TvMT)(\rho_{\text{altL}}(M) \otimes \rho_{\text{L}}(M))(\Phi^{-1}(v)) = \Phi^{-1}((M^{-1})^T v M^T) where Φ−1\Phi^{-1} is the inverse isomorphism `altLeftLeftToMatrix.symm`, ρaltL\rho_{\text{altL}} and ρL\rho_{\text{L}} are the representations of SL(2,C)SL(2, \mathbb{C}) on ValtLV_{\text{altL}} and VLV_{\text{L}}, respectively, (M−1)T(M^{-1})^T is the transpose of the inverse matrix of MM, and MTM^T is the transpose matrix of MM.

theorem

The SL(2,C)SL(2, \mathbb{C}) action on VR⊗VRV_R \otimes V_R via Φ−1\Phi^{-1} is equivalent to v↦MˉvMˉTv \mapsto \bar{M} v \bar{M}^{\text{T}}

Let VRV_R be the vector space of right-handed Weyl spinors. Let Φ:VR⊗VR→M2×2(C)\Phi: V_R \otimes V_R \to M_{2 \times 2}(\mathbb{C}) be the complex linear equivalence `rightRightToMatrix` that identifies a tensor with a 2×22 \times 2 complex matrix. For any matrix v∈M2×2(C)v \in M_{2 \times 2}(\mathbb{C}) and any group element M∈SL(2,C)M \in SL(2, \mathbb{C}), the representation of SL(2,C)SL(2, \mathbb{C}) on the tensor product space satisfies: (ρR(M)⊗ρR(M))(Φ−1(v))=Φ−1(MˉvMˉT)(\rho_R(M) \otimes \rho_R(M))(\Phi^{-1}(v)) = \Phi^{-1}(\bar{M} v \bar{M}^{\text{T}}) where Φ−1\Phi^{-1} is the inverse isomorphism `rightRightToMatrix.symm`, ρR\rho_R is the group representation on VRV_R, Mˉ\bar{M} is the complex conjugate of the matrix MM, and MˉT\bar{M}^{\text{T}} is its transpose.

theorem

The SL(2,C)SL(2, \mathbb{C}) action on ValtRight⊗ValtRightV_{\text{altRight}} \otimes V_{\text{altRight}} via Φ−1\Phi^{-1} is equivalent to v↦(M−1)†v((M−1)†)Tv \mapsto (M^{-1})^\dagger v ((M^{-1})^\dagger)^T

Let ValtRightV_{\text{altRight}} be the vector space associated with alternative right-handed Weyl fermions, and let ρaltRight\rho_{\text{altRight}} be the representation of SL(2,C)SL(2, \mathbb{C}) on ValtRightV_{\text{altRight}}. Let Φ:ValtRight⊗ValtRight→M2×2(C)\Phi: V_{\text{altRight}} \otimes V_{\text{altRight}} \to M_{2 \times 2}(\mathbb{C}) be the complex linear equivalence `altRightAltRightToMatrix`. For any matrix v∈M2×2(C)v \in M_{2 \times 2}(\mathbb{C}) and any group element M∈SL(2,C)M \in SL(2, \mathbb{C}), the representation of SL(2,C)SL(2, \mathbb{C}) on the tensor product space satisfies: (ρaltRight(M)⊗ρaltRight(M))(Φ−1(v))=Φ−1((M−1)†v((M−1)†)T)(\rho_{\text{altRight}}(M) \otimes \rho_{\text{altRight}}(M))(\Phi^{-1}(v)) = \Phi^{-1}\left((M^{-1})^\dagger v ((M^{-1})^\dagger)^T\right) where Φ−1\Phi^{-1} is the inverse isomorphism `altRightAltRightToMatrix.symm`, (M−1)†(M^{-1})^\dagger denotes the conjugate transpose of the inverse of MM, and TT denotes the transpose.

theorem

The SL(2,C)SL(2, \mathbb{C}) action on Φ−1(v)\Phi^{-1}(v) for VR⊗ValtRV_R \otimes V_{\text{alt}R} is Φ−1(Mˉv((M−1)†)T)\Phi^{-1}(\bar{M} v ((M^{-1})^\dagger)^T)

Let VRV_R and ValtRV_{\text{alt}R} be the vector spaces of right-handed and alternative right-handed Weyl fermions, respectively. Let Φ:VR⊗ValtR→≅Mat2×2(C)\Phi: V_R \otimes V_{\text{alt}R} \xrightarrow{\cong} \text{Mat}_{2 \times 2}(\mathbb{C}) be the C\mathbb{C}-linear equivalence `rightAltRightToMatrix` that identifies the tensor product space with 2×22 \times 2 complex matrices. For any matrix v∈Mat2×2(C)v \in \text{Mat}_{2 \times 2}(\mathbb{C}) and any group element M∈SL(2,C)M \in SL(2, \mathbb{C}), the group action on the pre-image of vv under Φ\Phi satisfies: (ρR(M)⊗ρaltR(M))(Φ−1(v))=Φ−1(Mˉv((M−1)†)T)(\rho_R(M) \otimes \rho_{\text{alt}R}(M)) (\Phi^{-1}(v)) = \Phi^{-1} \left( \bar{M} v ((M^{-1})^\dagger)^T \right) where Φ−1\Phi^{-1} is the inverse map `rightAltRightToMatrix.symm`, ρR\rho_R and ρaltR\rho_{\text{alt}R} are the group representations on VRV_R and ValtRV_{\text{alt}R}, Mˉ\bar{M} denotes the entry-wise complex conjugate of MM, M−1M^{-1} is the matrix inverse, and †\dagger and TT denote the conjugate transpose and transpose operations, respectively.

theorem

SL(2,C)SL(2, \mathbb{C}) action on Φ−1(v)\Phi^{-1}(v) for altRightHanded⊗rightHanded\text{altRightHanded} \otimes \text{rightHanded}

Let Φ:V→M2×2(C)\Phi: V \to M_{2 \times 2}(\mathbb{C}) be the C\mathbb{C}-linear equivalence `altRightRightToMatrix` that maps the vector space VV of the tensor product of an alternate right-handed Weyl fermion and a right-handed Weyl fermion to the space of 2×22 \times 2 complex matrices. For any matrix v∈M2×2(C)v \in M_{2 \times 2}(\mathbb{C}) and any group element M∈SL(2,C)M \in SL(2, \mathbb{C}), the action of MM on the pre-image of vv under Φ\Phi satisfies: (ρaltRight(M)⊗ρright(M))(Φ−1(v))=Φ−1((M−1)†vM‾⊤)(\rho_{\text{altRight}}(M) \otimes \rho_{\text{right}}(M)) (\Phi^{-1}(v)) = \Phi^{-1} \left( (M^{-1})^\dagger v \overline{M}^\top \right) where Φ−1\Phi^{-1} is the inverse map of the linear equivalence, ρaltRight\rho_{\text{altRight}} and ρright\rho_{\text{right}} are the representations of SL(2,C)SL(2, \mathbb{C}) on the alternate right-handed and right-handed Weyl fermion spaces respectively, (M−1)†(M^{-1})^\dagger denotes the conjugate transpose of the inverse of MM, and M‾⊤\overline{M}^\top denotes the transpose of the complex conjugate of MM.

theorem

SL(2,C)SL(2, \mathbb{C}) action on Φ−1(v)\Phi^{-1}(v) for altLeftHanded⊗altRightHanded\text{altLeftHanded} \otimes \text{altRightHanded}

Let Φ:V→Mat2×2(C)\Phi: V \to \text{Mat}_{2 \times 2}(\mathbb{C}) be the C\mathbb{C}-linear equivalence `altLeftAltRightToMatrix` that maps the vector space VV of the tensor product of an alternating left-handed Weyl fermion and an alternating right-handed Weyl fermion to the space of 2×22 \times 2 complex matrices. For any matrix v∈Mat2×2(C)v \in \text{Mat}_{2 \times 2}(\mathbb{C}) and any M∈SL(2,C)M \in SL(2, \mathbb{C}), the action of MM on the pre-image of vv under Φ\Phi satisfies: (ρL(M)⊗ρR(M))(Φ−1(v))=Φ−1((M−1)TvM−1‾) (\rho_L(M) \otimes \rho_R(M)) (\Phi^{-1}(v)) = \Phi^{-1} \left( (M^{-1})^T v \overline{M^{-1}} \right) where Φ−1\Phi^{-1} is the inverse map of the linear equivalence, ρL\rho_L and ρR\rho_R are the representations of SL(2,C)SL(2, \mathbb{C}) on the alternating left-handed and alternating right-handed Weyl fermion spaces respectively, (M−1)T(M^{-1})^T is the transpose of the inverse of MM, and M−1‾\overline{M^{-1}} is the complex conjugate of the inverse of MM.

theorem

SL(2,C)SL(2, \mathbb{C}) action on Φ−1(v)\Phi^{-1}(v) for VL⊗VRV_L \otimes V_R is MvM†M v M^\dagger

Let Φ:VL⊗VR≅Mat2×2(C)\Phi: V_L \otimes V_R \cong \text{Mat}_{2 \times 2}(\mathbb{C}) be the C\mathbb{C}-linear equivalence `leftRightToMatrix` between the tensor product of the vector spaces for left-handed and right-handed Weyl fermions and the space of 2×22 \times 2 complex matrices. For any matrix v∈Mat2×2(C)v \in \text{Mat}_{2 \times 2}(\mathbb{C}) and any matrix M∈SL(2,C)M \in SL(2, \mathbb{C}), the action of the group on the pre-image of vv under Φ\Phi satisfies: (ρL(M)⊗ρR(M))(Φ−1(v))=Φ−1(MvM†) (\rho_L(M) \otimes \rho_R(M)) (\Phi^{-1}(v)) = \Phi^{-1}(M v M^\dagger) where Φ−1\Phi^{-1} is the inverse of the linear equivalence, ρL(M)\rho_L(M) and ρR(M)\rho_R(M) are the representations of SL(2,C)SL(2, \mathbb{C}) on VLV_L and VRV_R respectively, and M†M^\dagger denotes the conjugate transpose (Hermitian conjugate) of MM.

theorem

SL(2,C)SL(2, \mathbb{C}) action on Φ−1(v)\Phi^{-1}(v) for altLeftHanded⊗altRightHanded\text{altLeftHanded} \otimes \text{altRightHanded} is (MT)−1v((MT)−1)†(M^T)^{-1} v ((M^T)^{-1})^\dagger for self-adjoint vv

Let Φ:V→Mat2×2(C)\Phi: V \to \text{Mat}_{2 \times 2}(\mathbb{C}) be the C\mathbb{C}-linear equivalence `altLeftAltRightToMatrix` that maps the vector space VV of the tensor product of an alternating left-handed Weyl fermion and an alternating right-handed Weyl fermion to the space of 2×22 \times 2 complex matrices. For any self-adjoint matrix v∈Mat2×2(C)v \in \text{Mat}_{2 \times 2}(\mathbb{C}) (v=v†v = v^\dagger) and any M∈SL(2,C)M \in SL(2, \mathbb{C}), the action of the group on the pre-image of vv under Φ\Phi satisfies: (ρL(M)⊗ρR(M))(Φ−1(v))=Φ−1((MT)−1v((MT)−1)†) (\rho_L(M) \otimes \rho_R(M)) (\Phi^{-1}(v)) = \Phi^{-1} \left( (M^T)^{-1} v ((M^T)^{-1})^\dagger \right) where Φ−1\Phi^{-1} is the inverse map of the linear equivalence, ρL\rho_L and ρR\rho_R are the representations of SL(2,C)SL(2, \mathbb{C}) on the alternating left-handed and alternating right-handed Weyl fermion spaces respectively, (MT)−1(M^T)^{-1} is the inverse of the transpose of MM, and †\dagger denotes the conjugate transpose.

theorem

SL(2,C)SL(2, \mathbb{C}) action on Φ−1(v)\Phi^{-1}(v) for VL⊗VRV_L \otimes V_R is MvM†M v M^\dagger for self-adjoint vv

Let Φ:VL⊗VR≅Mat2×2(C)\Phi: V_L \otimes V_R \cong \text{Mat}_{2 \times 2}(\mathbb{C}) be the C\mathbb{C}-linear equivalence `leftRightToMatrix` between the tensor product of the vector spaces for left-handed and right-handed Weyl fermions and the space of 2×22 \times 2 complex matrices. For any matrix M∈SL(2,C)M \in SL(2, \mathbb{C}) and any self-adjoint matrix v∈Mat2×2(C)v \in \text{Mat}_{2 \times 2}(\mathbb{C}) (v=v†v = v^\dagger), the action of the representations ρL(M)\rho_L(M) and ρR(M)\rho_R(M) on the pre-image of vv under Φ\Phi satisfies: (ρL(M)⊗ρR(M))(Φ−1(v))=Φ−1(MvM†) (\rho_L(M) \otimes \rho_R(M)) (\Phi^{-1}(v)) = \Phi^{-1}(M v M^\dagger) where Φ−1\Phi^{-1} is the inverse of the linear equivalence, and M†M^\dagger denotes the conjugate transpose (Hermitian conjugate) of MM.