Physlib

Physlib.Relativity.LorentzGroup.Basic

The Lorentz Group

We define the Lorentz group.

References

- *Lorentz Transformations, Rotations, and Boosts*, Jaffe. <https://cdn.ku.edu.tr/cdn/files/amostafazadeh/phys517_518/phys517_2016f/Handouts/A_Jaffi_Lorentz_Group.pdf>

Matrices which preserves the Minkowski metric

We start studying the properties of matrices which preserve `ηLin`. These matrices form the Lorentz group, which we will define in the next section at `lorentzGroup`.

Membership conditions

The Lorentz group as a group

Transpose of a Lorentz transformation

Negation of a Lorentz transformation

Lorentz group as a topological group

We now show that the Lorentz group is a topological group. We do this by showing that the natural map from the Lorentz group to `GL (Fin 4) ℝ` is an embedding.

To Complex matrices

Equality conditions

45 declarations

definition

Lorentz group L\mathcal{L} for dd spatial dimensions

For a given natural number dd, the Lorentz group is the set of real matrices Λ\Lambda of dimension (1+d)×(1+d)(1+d) \times (1+d) that satisfy the condition ΛΛ=I\Lambda \Lambda^* = I, where II is the identity matrix and Λ=ηΛTη\Lambda^* = \eta \Lambda^T \eta is the Minkowski dual of Λ\Lambda, defined using the Minkowski metric η=diag(1,1,,1)\eta = \text{diag}(1, -1, \dots, -1).

definition

Notation L\mathcal{L} for the Lorentz group

The symbol L\mathcal{L} is defined as the mathematical notation for the Lorentz group, which consists of real matrices of size (1+d)×(1+d)(1+d) \times (1+d) that preserve the Minkowski metric.

theorem

ΛL    ΛΛ=I\Lambda \in \mathcal{L} \iff \Lambda \Lambda^* = I

For a given natural number dd and a real matrix Λ\Lambda of dimension (1+d)×(1+d)(1+d) \times (1+d), Λ\Lambda belongs to the Lorentz group L\mathcal{L} if and only if ΛΛ=I\Lambda \Lambda^* = I, where Λ\Lambda^* is the Minkowski dual of Λ\Lambda defined as ηΛTη\eta \Lambda^T \eta, and II is the identity matrix.

theorem

ΛL    ΛΛ=I\Lambda \in \mathcal{L} \iff \Lambda^* \Lambda = I

For a given natural number dd and a real matrix Λ\Lambda of dimension (1+d)×(1+d)(1+d) \times (1+d), Λ\Lambda belongs to the Lorentz group L\mathcal{L} if and only if ΛΛ=I\Lambda^* \Lambda = I, where Λ\Lambda^* is the Minkowski dual of Λ\Lambda (defined as ηΛTη\eta \Lambda^T \eta using the Minkowski metric η\eta) and II is the identity matrix.

theorem

ΛL    ΛTL\Lambda \in \mathcal{L} \iff \Lambda^T \in \mathcal{L}

For any natural number dd and any real matrix Λ\Lambda of dimension (1+d)×(1+d)(1+d) \times (1+d), Λ\Lambda belongs to the Lorentz group L\mathcal{L} if and only if its transpose ΛT\Lambda^T belongs to the Lorentz group.

theorem

ΛL    ΛL\Lambda \in \mathcal{L} \iff -\Lambda \in \mathcal{L}

For any real matrix Λ\Lambda of dimension (1+d)×(1+d)(1+d) \times (1+d), Λ\Lambda belongs to the Lorentz group L\mathcal{L} if and only if its negation Λ-\Lambda belongs to the Lorentz group.

theorem

Λ,ΛL    ΛΛL\Lambda, \Lambda' \in \mathcal{L} \implies \Lambda \Lambda' \in \mathcal{L}

For any two matrices Λ\Lambda and Λ\Lambda' that are members of the Lorentz group L\mathcal{L} for dd spatial dimensions, their matrix product ΛΛ\Lambda \Lambda' is also a member of the Lorentz group. The Lorentz group is defined as the set of real (1+d)×(1+d)(1+d) \times (1+d) matrices Λ\Lambda satisfying ΛΛ=I\Lambda \Lambda^* = I, where Λ=ηΛTη\Lambda^* = \eta \Lambda^T \eta is the Minkowski dual and η\eta is the Minkowski metric diag(1,1,,1)\text{diag}(1, -1, \dots, -1).

theorem

ILI \in \mathcal{L}

For a given natural number dd, the identity matrix II of dimension (1+d)×(1+d)(1+d) \times (1+d) is an element of the Lorentz group L\mathcal{L}.

theorem

ΛL    ΛL\Lambda \in \mathcal{L} \implies \Lambda^* \in \mathcal{L}

For any matrix Λ\Lambda in the Lorentz group L\mathcal{L} for dd spatial dimensions, its Minkowski dual Λ=ηΛTη\Lambda^* = \eta \Lambda^T \eta is also an element of the Lorentz group L\mathcal{L}.

theorem

ΛL    ΛTηΛ=η\Lambda \in \mathcal{L} \iff \Lambda^T \eta \Lambda = \eta

For a given natural number dd representing spatial dimensions, a real matrix Λ\Lambda of dimension (1+d)×(1+d)(1+d) \times (1+d) belongs to the Lorentz group L\mathcal{L} if and only if it satisfies the condition ΛTηΛ=η\Lambda^T \eta \Lambda = \eta where η\eta is the (1+d)×(1+d)(1+d) \times (1+d) Minkowski matrix diag(1,1,,1)\text{diag}(1, -1, \dots, -1) and ΛT\Lambda^T denotes the transpose of Λ\Lambda.

instance

The Lorentz group L\mathcal{L} is a group under matrix multiplication

For a given natural number dd representing spatial dimensions, the Lorentz group L\mathcal{L} (the set of real matrices Λ\Lambda of dimension (1+d)×(1+d)(1+d) \times (1+d) satisfying ΛTηΛ=η\Lambda^T \eta \Lambda = \eta) forms a group under matrix multiplication. The identity element of the group is the identity matrix II, and the inverse of an element ΛL\Lambda \in \mathcal{L} is given by its Minkowski dual Λ=ηΛTη\Lambda^* = \eta \Lambda^T \eta, where η=diag(1,1,,1)\eta = \text{diag}(1, -1, \dots, -1).

instance

The Lorentz group L\mathcal{L} as a topological space

The Lorentz group L\mathcal{L} for dd spatial dimensions is equipped with a topological space structure. This topology is the subspace topology (subtype topology) inherited from the space of all (1+d)×(1+d)(1+d) \times (1+d) real matrices M1+d(R)\text{M}_{1+d}(\mathbb{R}).

theorem

The inverse of a Lorentz transformation Λ\Lambda is its Minkowski dual Λ\Lambda^*

For any element Λ\Lambda of the Lorentz group L\mathcal{L} in dd spatial dimensions, the group inverse Λ1\Lambda^{-1} is equal to its Minkowski dual Λ\Lambda^*, which is defined as Λ=ηΛTη\Lambda^* = \eta \Lambda^T \eta, where η=diag(1,1,,1)\eta = \text{diag}(1, -1, \dots, -1) is the Minkowski metric.

theorem

The group inverse of ΛL\Lambda \in \mathcal{L} is its matrix inverse

For any element Λ\Lambda of the Lorentz group L\mathcal{L} in dd spatial dimensions, the underlying matrix of the group inverse Λ1\Lambda^{-1} is equal to the matrix inverse of Λ\Lambda.

instance

Lorentz matrices ΛL\Lambda \in \mathcal{L} are invertible

For any element Λ\Lambda of the Lorentz group L\mathcal{L} in dd spatial dimensions, the underlying (1+d)×(1+d)(1+d) \times (1+d) real matrix is invertible.

theorem

Λ1Λ=I\Lambda^{-1} \Lambda = I for ΛL\Lambda \in \mathcal{L}

For any element Λ\Lambda of the Lorentz group L\mathcal{L} in dd spatial dimensions, the product of its matrix inverse Λ1\Lambda^{-1} and the matrix Λ\Lambda is the identity matrix II, that is: Λ1Λ=I\Lambda^{-1} \Lambda = I

theorem

ΛΛ1=I\Lambda \Lambda^{-1} = I for ΛL\Lambda \in \mathcal{L}

For any element Λ\Lambda in the Lorentz group L\mathcal{L} for dd spatial dimensions, the product of its matrix representation and its inverse matrix Λ1\Lambda^{-1} is the identity matrix II, i.e., ΛΛ1=I\Lambda \Lambda^{-1} = I.

theorem

ΛηΛT=η\Lambda \eta \Lambda^T = \eta for ΛL\Lambda \in \mathcal{L}

Let dd be a natural number and let Λ\Lambda be an element of the Lorentz group L\mathcal{L} for dd spatial dimensions. Then the matrix representation of Λ\Lambda satisfies the identity ΛηΛT=η \Lambda \eta \Lambda^T = \eta where η\eta is the (1+d)×(1+d)(1+d) \times (1+d) Minkowski matrix diag(1,1,,1)\text{diag}(1, -1, \dots, -1) and ΛT\Lambda^T denotes the transpose of Λ\Lambda.

theorem

ΛTηΛ=η\Lambda^T \eta \Lambda = \eta for ΛL\Lambda \in \mathcal{L}

Let dd be a natural number and let Λ\Lambda be an element of the Lorentz group L\mathcal{L} for dd spatial dimensions. Then the matrix representation of Λ\Lambda satisfies the identity ΛTηΛ=η \Lambda^T \eta \Lambda = \eta where η\eta is the (1+d)×(1+d)(1+d) \times (1+d) Minkowski matrix diag(1,1,,1)\text{diag}(1, -1, \dots, -1) and ΛT\Lambda^T denotes the transpose of Λ\Lambda.

definition

Transpose ΛT\Lambda^T of a Lorentz transformation Λ\Lambda

For an element Λ\Lambda in the Lorentz group LorentzGroup d\text{LorentzGroup } d (the set of real (1+d)×(1+d)(1+d) \times (1+d) matrices preserving the Minkowski metric), this function returns its matrix transpose ΛT\Lambda^T, which is also an element of the Lorentz group.

theorem

IT=II^T = I in the Lorentz group

Let II be the identity element of the Lorentz group L\mathcal{L} for dd spatial dimensions. The transpose of the identity element is equal to the identity element itself, i.e., IT=II^T = I.

theorem

(ΛΛ)T=ΛTΛT(\Lambda \Lambda')^T = \Lambda'^T \Lambda^T

For any two Lorentz transformations Λ\Lambda and Λ\Lambda' in the Lorentz group L\mathcal{L} for dd spatial dimensions, the transpose of their product is equal to the product of their transposes in reverse order: (ΛΛ)T=ΛTΛT (\Lambda \Lambda')^T = \Lambda'^T \Lambda^T where the product ΛΛ\Lambda \Lambda' is the group multiplication (matrix multiplication) and TT denotes the matrix transpose.

theorem

The matrix of the transpose ΛT\Lambda^T is the transpose of the matrix Λ\Lambda

For any element Λ\Lambda of the Lorentz group for dd spatial dimensions, the underlying matrix of the transpose of Λ\Lambda is equal to the transpose of the matrix representation of Λ\Lambda. That is, (ΛT)ij=Λji(\Lambda^T)_{ij} = \Lambda_{ji}.

theorem

(ΛT)1=(Λ1)T(\Lambda^T)^{-1} = (\Lambda^{-1})^T for ΛL\Lambda \in \mathcal{L}

For any element Λ\Lambda of the Lorentz group L\mathcal{L} for dd spatial dimensions, the group inverse of its transpose is equal to the transpose of its group inverse: (ΛT)1=(Λ1)T (\Lambda^T)^{-1} = (\Lambda^{-1})^T where ΛT\Lambda^T denotes the matrix transpose and Λ1\Lambda^{-1} denotes the group inverse within the Lorentz group.

theorem

Λη=η(Λ1)T\Lambda \eta = \eta (\Lambda^{-1})^T for ΛL\Lambda \in \mathcal{L}

For any element Λ\Lambda of the Lorentz group L\mathcal{L} for dd spatial dimensions, let η\eta be the (1+d)×(1+d)(1+d) \times (1+d) Minkowski matrix diag(1,1,,1)\text{diag}(1, -1, \dots, -1). Then the matrix representation of Λ\Lambda satisfies the identity: Λη=η(Λ1)T\Lambda \eta = \eta (\Lambda^{-1})^T where Λ1\Lambda^{-1} denotes the group inverse of Λ\Lambda and ()T(\cdot)^T denotes the matrix transpose.

theorem

ηΛ=(Λ1)Tη\eta \Lambda = (\Lambda^{-1})^T \eta for ΛL\Lambda \in \mathcal{L}

Let dd be a natural number and let Λ\Lambda be an element of the Lorentz group L\mathcal{L} for dd spatial dimensions. Let η\eta be the (1+d)×(1+d)(1+d) \times (1+d) Minkowski matrix diag(1,1,,1)\text{diag}(1, -1, \dots, -1). Then the following identity holds: ηΛ=(Λ1)Tη \eta \Lambda = (\Lambda^{-1})^T \eta where Λ\Lambda denotes the matrix representation of the Lorentz transformation, Λ1\Lambda^{-1} is its group inverse, and (Λ1)T(\Lambda^{-1})^T is the transpose of that inverse.

instance

Negation of a Lorentz transformation Λ\Lambda

For any element Λ\Lambda in the Lorentz group L\mathcal{L} of dd spatial dimensions, its negation Λ-\Lambda is defined as the entry-wise negation of the matrix Λ\Lambda.

theorem

Matrix representation of Λ-\Lambda is Λ-\Lambda

Let Λ\Lambda be an element of the Lorentz group L\mathcal{L} for dd spatial dimensions. The matrix representation of the negation Λ-\Lambda is equal to the entry-wise negation of the matrix representation of Λ\Lambda.

theorem

(Λ)1=Λ1(-\Lambda)^{-1} = -\Lambda^{-1} in the Lorentz group

Let Λ\Lambda be an element of the Lorentz group L\mathcal{L} for dd spatial dimensions. The group inverse of the negation of Λ\Lambda is equal to the negation of the group inverse of Λ\Lambda, i.e., (Λ)1=Λ1(-\Lambda)^{-1} = -\Lambda^{-1}.

definition

Group homomorphism from the Lorentz group L\mathcal{L} to GL(1+d,R)GL(1+d, \mathbb{R})

For a given natural number dd representing the number of spatial dimensions, this is the group homomorphism that maps an element Λ\Lambda of the Lorentz group L\mathcal{L} to the general linear group GL(1+d,R)GL(1+d, \mathbb{R}). It identifies each Lorentz matrix as an invertible real matrix of dimension (1+d)×(1+d)(1+d) \times (1+d).

theorem

The map toGL:LGL(1+d,R)\text{toGL} : \mathcal{L} \to GL(1+d, \mathbb{R}) is injective

For a given natural number dd representing the number of spatial dimensions, the group homomorphism toGL:LGL(1+d,R)\text{toGL} : \mathcal{L} \to GL(1+d, \mathbb{R}), which maps an element of the Lorentz group to its corresponding matrix in the general linear group, is injective.

definition

Homomorphism from the Lorentz group L\mathcal{L} to M1+d(R)×M1+d(R)opM_{1+d}(\mathbb{R}) \times M_{1+d}(\mathbb{R})^{\text{op}}

For a given natural number dd representing the number of spatial dimensions, this is the group homomorphism from the Lorentz group L\mathcal{L} to the product of the monoid of (1+d)×(1+d)(1+d) \times (1+d) real matrices and its opposite monoid, denoted M1+d(R)×M1+d(R)opM_{1+d}(\mathbb{R}) \times M_{1+d}(\mathbb{R})^{\text{op}}. For any Lorentz transformation ΛL\Lambda \in \mathcal{L}, the map is defined as Λ(Λ,Λ)\Lambda \mapsto (\Lambda, \Lambda^*), where Λ=ηΛTη\Lambda^* = \eta \Lambda^T \eta is the Minkowski dual (which coincides with the inverse Λ1\Lambda^{-1} for elements of the Lorentz group) and η=diag(1,1,,1)\eta = \text{diag}(1, -1, \dots, -1) is the Minkowski metric.

theorem

toProd(Λ)=(Λ,Λ)\text{toProd}(\Lambda) = (\Lambda, \Lambda^*) for the Lorentz group L\mathcal{L}

Let L\mathcal{L} be the Lorentz group for dd spatial dimensions, consisting of real matrices of dimension (1+d)×(1+d)(1+d) \times (1+d). For any Lorentz transformation ΛL\Lambda \in \mathcal{L}, the value of the group homomorphism toProd:LM1+d(R)×M1+d(R)op\text{toProd} : \mathcal{L} \to M_{1+d}(\mathbb{R}) \times M_{1+d}(\mathbb{R})^{\text{op}} is given by the pair (Λ,Λ)(\Lambda, \Lambda^*), where Λ\Lambda^* is the Minkowski dual of Λ\Lambda defined by Λ=ηΛTη\Lambda^* = \eta \Lambda^T \eta (and viewed as an element of the opposite monoid M1+d(R)opM_{1+d}(\mathbb{R})^{\text{op}}), where η=diag(1,1,,1)\eta = \text{diag}(1, -1, \dots, -1) is the Minkowski metric.

theorem

The map Λ(Λ,Λ)\Lambda \mapsto (\Lambda, \Lambda^*) is injective

For the Lorentz group L\mathcal{L} in dd spatial dimensions, the group homomorphism toProd:LM1+d(R)×M1+d(R)op\text{toProd} : \mathcal{L} \to M_{1+d}(\mathbb{R}) \times M_{1+d}(\mathbb{R})^{\text{op}} defined by Λ(Λ,Λ)\Lambda \mapsto (\Lambda, \Lambda^*) is injective, where Λ=ηΛTη\Lambda^* = \eta \Lambda^T \eta is the Minkowski dual and η=diag(1,1,,1)\eta = \text{diag}(1, -1, \dots, -1) is the Minkowski metric.

theorem

The map Λ(Λ,Λ)\Lambda \mapsto (\Lambda, \Lambda^*) is continuous

For the Lorentz group L\mathcal{L} in dd spatial dimensions, the map Λ(Λ,Λ)\Lambda \mapsto (\Lambda, \Lambda^*) from L\mathcal{L} to the product space M1+d(R)×M1+d(R)opM_{1+d}(\mathbb{R}) \times M_{1+d}(\mathbb{R})^{\text{op}} is continuous, where Λ=ηΛTη\Lambda^* = \eta \Lambda^T \eta is the Minkowski dual and η=diag(1,1,,1)\eta = \text{diag}(1, -1, \dots, -1) is the Minkowski metric.

theorem

The map Λ(Λ,Λ)\Lambda \mapsto (\Lambda, \Lambda^*) is a topological embedding

For the Lorentz group L\mathcal{L} in dd spatial dimensions, the map Λ(Λ,Λ)\Lambda \mapsto (\Lambda, \Lambda^*) from L\mathcal{L} to the product space M1+d(R)×M1+d(R)opM_{1+d}(\mathbb{R}) \times M_{1+d}(\mathbb{R})^{\text{op}} is a topological embedding. Here, M1+d(R)M_{1+d}(\mathbb{R}) is the space of (1+d)×(1+d)(1+d) \times (1+d) real matrices, M1+d(R)opM_{1+d}(\mathbb{R})^{\text{op}} is its opposite monoid, Λ=ηΛTη\Lambda^* = \eta \Lambda^T \eta is the Minkowski dual, and η=diag(1,1,,1)\eta = \text{diag}(1, -1, \dots, -1) is the Minkowski metric.

theorem

The map toGL:LGL(1+d,R)\text{toGL} : \mathcal{L} \to GL(1+d, \mathbb{R}) is a topological embedding

For a given natural number dd representing the number of spatial dimensions, the natural map toGL:LGL(1+d,R)\text{toGL} : \mathcal{L} \to GL(1+d, \mathbb{R}), which identifies each element of the Lorentz group L\mathcal{L} as an invertible (1+d)×(1+d)(1+d) \times (1+d) real matrix, is a topological embedding. Here, the Lorentz group L\mathcal{L} is equipped with the subspace topology inherited from the space of all real matrices M1+d(R)M_{1+d}(\mathbb{R}).

instance

The Lorentz group L\mathcal{L} is a topological group

For a given natural number dd representing the number of spatial dimensions, the Lorentz group L\mathcal{L} (the group of (1+d)×(1+d)(1+d) \times (1+d) real matrices that preserve the Minkowski metric η\eta) is a topological group. This structure is defined using the subspace topology inherited from the space of all real matrices M1+d(R)M_{1+d}(\mathbb{R}), under which the group operations of matrix multiplication and inversion are continuous.

definition

Monoid homomorphism from the Lorentz group L\mathcal{L} to complex matrices

For a given natural number dd representing spatial dimensions, this definition provides a monoid homomorphism from the Lorentz group L\mathcal{L} to the set of (1+d)×(1+d)(1+d) \times (1+d) complex matrices. Specifically, it maps each real matrix ΛL\Lambda \in \mathcal{L} to a complex matrix by applying the canonical embedding of real numbers into complex numbers, RC\mathbb{R} \hookrightarrow \mathbb{C}, to each entry of the matrix.

instance

toComplex(Λ)\text{toComplex}(\Lambda) is invertible for ΛL\Lambda \in \mathcal{L}

For any Lorentz transformation Λ\Lambda in the Lorentz group L\mathcal{L} for dd spatial dimensions, the (1+d)×(1+d)(1+d) \times (1+d) complex matrix obtained by mapping the real entries of Λ\Lambda to the complex field C\mathbb{C} is invertible. The inverse of this matrix is the image of the group inverse Λ1\Lambda^{-1} under the same mapping.

theorem

(toComplex Λ)1=toComplex (Λ1)(\text{toComplex } \Lambda)^{-1} = \text{toComplex } (\Lambda^{-1}) for ΛL\Lambda \in \mathcal{L}

For any element Λ\Lambda in the Lorentz group L\mathcal{L} for dd spatial dimensions, the matrix inverse of its complex representation is equal to the complex representation of its group inverse. That is, (toComplex Λ)1=toComplex (Λ1) (\text{toComplex } \Lambda)^{-1} = \text{toComplex } (\Lambda^{-1}) where toComplex\text{toComplex} is the monoid homomorphism that embeds real matrices into the space of complex matrices.

theorem

ΛηΛT=η\Lambda \eta \Lambda^T = \eta for complexified Lorentz transformations ΛL\Lambda \in \mathcal{L}

Let dd be a natural number representing the number of spatial dimensions. For any element Λ\Lambda in the Lorentz group L\mathcal{L} for dd spatial dimensions, its representation as a complex matrix satisfies the identity ΛηΛT=η \Lambda \eta \Lambda^T = \eta where η\eta is the (1+d)×(1+d)(1+d) \times (1+d) Minkowski matrix diag(1,1,,1)\text{diag}(1, -1, \dots, -1) with entries embedded into the complex numbers C\mathbb{C}, and ΛT\Lambda^T denotes the transpose of the matrix.

theorem

ΛCTηCΛC=ηC\Lambda_\mathbb{C}^T \eta_\mathbb{C} \Lambda_\mathbb{C} = \eta_\mathbb{C} for ΛL\Lambda \in \mathcal{L}

For a given natural number dd and an element Λ\Lambda of the Lorentz group L\mathcal{L} (the group of real (1+d)×(1+d)(1+d) \times (1+d) matrices preserving the Minkowski metric), let ΛC\Lambda_\mathbb{C} be the complex matrix obtained by the canonical embedding of the real entries of Λ\Lambda into C\mathbb{C}. Then the following identity holds: ΛCTηCΛC=ηC \Lambda_\mathbb{C}^T \eta_\mathbb{C} \Lambda_\mathbb{C} = \eta_\mathbb{C} where ηC\eta_\mathbb{C} is the (1+d)×(1+d)(1+d) \times (1+d) Minkowski matrix diag(1,1,,1)\text{diag}(1, -1, \dots, -1) with entries considered as complex numbers, and ΛCT\Lambda_\mathbb{C}^T denotes the transpose of ΛC\Lambda_\mathbb{C}.

theorem

ΛCvC=(Λv)C\Lambda_{\mathbb{C}} v_{\mathbb{C}} = (\Lambda v)_{\mathbb{C}} for Lorentz transformations Λ\Lambda and real vectors vv

For any natural number dd representing the number of spatial dimensions, any element Λ\Lambda of the Lorentz group L\mathcal{L}, and any real vector vR1+dv \in \mathbb{R}^{1+d}, the following identity holds: ΛCvC=(Λv)C \Lambda_{\mathbb{C}} v_{\mathbb{C}} = (\Lambda v)_{\mathbb{C}} where ΛC\Lambda_{\mathbb{C}} denotes the complex matrix obtained by embedding the real entries of Λ\Lambda into C\mathbb{C}, and vCv_{\mathbb{C}} denotes the complex vector obtained by embedding the real entries of vv into C\mathbb{C}.

definition

Parity transformation PLP \in \mathcal{L}

The parity transformation is the element of the Lorentz group L\mathcal{L} in dd spatial dimensions represented by the Minkowski matrix η=diag(1,1,,1)\eta = \text{diag}(1, -1, \dots, -1). It acts on spacetime coordinates by preserving the time component and inverting the spatial components.