The Pauli Algebra Cl(3) Is Frobenius In Many Ways Linear operators over a 8-dimensional vector space representing Pauli algebra Ref:
We need the Axiom LinearOperator library. fricas (1) -> )library CARTEN ARITY CMONAL CPROP CLOP CALEY Use the following macros for convenient notation fricas -- summation macro Σ(x, Type: Void
fricas -- list macro Ξ(f, Type: Void
fricas -- subscript and superscripts macro sb == subscript Type: Void
fricas macro sp == superscript Type: Void
𝐋 is the domain of 8-dimensional linear operators over the rational functions ℚ (Expression Integer), i.e. ratio of polynomials with integer coefficients. fricas dim:=8
Type: PositiveInteger?
fricas macro ℒ == List Type: Void
fricas macro ℂ == CaleyDickson Type: Void
fricas macro ℚ == Expression Integer Type: Void
fricas 𝐋 := ClosedLinearOperator(OVAR ['1,
Type: Type
fricas 𝐞:ℒ 𝐋 := basisOut()
fricas 𝐝:ℒ 𝐋 := basisIn()
fricas I:𝐋:=[1] -- identity for composition
fricas X:𝐋:=[2,
fricas V:𝐋:=ev(1) -- evaluation
fricas Λ:𝐋:=co(1) -- co-evaluation
fricas equate(eq)==map((x, Type: Void
Now generate structure constants for Pauli Algebra The basis consists of the real and imaginary units. We use quaternion multiplication to form the "multiplication table" as a matrix. Then the structure constants can be obtained by dividing each matrix entry by the list of basis vectors. The Pauli Algebra as Cl(3) Basis: Each B.i is a Clifford number fricas q0:=sp('i,
Type: Symbol
fricas q1:=sp('j,
Type: Symbol
fricas q2:=sp('k,
Type: Symbol
fricas QQ:=CliffordAlgebra(3,
Type: Type
fricas B:ℒ QQ := [monomial(1,
fricas M:Matrix QQ := matrix Ξ(Ξ(B.i*B.j,
fricas S(y) == map(x +-> coefficient(recip(y)*x, Type: Void
fricas ѕ :=map(S, fricas Compiling function S with type CliffordAlgebra(3,
Type: List(List(List(Expression(Integer))))
fricas -- structure constants form a tensor operator Y := Σ(Σ(Σ(ѕ(i)(k)(j)*𝐞.i*𝐝.j*𝐝.k,
fricas matrix Ξ(Ξ((𝐞.i*𝐞.j)/Y,
fricas XY := X/Y; Units fricas e:=𝐞.1; i:=𝐞.2; j:=𝐞.3; k:=𝐞.4; ij:=𝐞.5; ik:=𝐞.6; jk:=𝐞.7; ijk:=𝐞.8; Multiplication of arbitrary quaternions and fricas a:=Σ(sb('a,
fricas b:=Σ(sb('b,
fricas (a*b)/Y
Multiplication is Associative fricas test( ( I Y ) / _ ( Y ) = _ ( Y I ) / _ ( Y ) )
Type: Boolean
A scalar product is denoted by the (2,0)-tensor fricas U:=Σ(Σ(script('u,
Definition 1We say that the scalar product is associative if the tensor equation holds: Y = Y U U In other words, if the (3,0)-tensor:
Using the LinearOperator domain in Axiom and some carefully chosen symbols we can easily enter expressions that are both readable and interpreted by Axiom as "graphical calculus" diagrams describing complex products and compositions of linear operators. fricas ω:𝐋 := _ ( Y I ) / _ U - _ ( I Y ) / _ U; Definition 2An algebra with a non-degenerate associative scalar product is called a [Frobenius Algebra]?. The Cartan-Killing Trace fricas Ú:= ( Y Λ ) / _ ( Y I ) / _ V
fricas Ù:= ( Λ Y ) / _ ( I Y ) / _ V
fricas test(Ù=Ú)
Type: Boolean
forms a non-degenerate associative scalar product for Y fricas Ũ := Ù
fricas test ( Y I ) / Ũ = ( I Y ) / Ũ
Type: Boolean
fricas determinant Ξ(Ξ(retract((𝐞.i * 𝐞.j)/Ũ),
Type: Expression(Integer)
General Solution Frobenius Form (co-unit) fricas d:=ε1*𝐝.1+εi*𝐝.2+εj*𝐝.3+εk*𝐝.4+εij*𝐝.5+εik*𝐝.6+εjk*𝐝.7+εijk*𝐝.8
fricas Ų:= Y/d
In general the pairing is not symmetric! fricas u1:=matrix Ξ(Ξ(retract((𝐞.i 𝐞.j)/Ų),
Type: Matrix(Expression(Integer))
The scalar product must be non-degenerate: fricas --Ů:=determinant u1 --factor(numer Ů)/factor(denom Ů) 1
Type: PositiveInteger?
Cartan-Killing is a special case fricas ck:=solve(equate(Ũ=Ų), fricas Compiling function equate with type Equation(ClosedLinearOperator( OrderedVariableList([1,
Type: List(Equation(Expression(Integer)))
Frobenius scalar product of "vector" quaternions and fricas a:=sb('a,
fricas b:=sb('b,
fricas (a,
fricas (b,
fricas (a,
Definition 3Co-scalar product Solve the Snake Relation as a system of linear equations. fricas mU:=inverse matrix Ξ(Ξ(retract((𝐞.i*𝐞.j)/Ų), Type: Union(Matrix(Expression(Integer)),
fricas Ω:=Σ(Σ(mU(i, fricas ΩX:=Ω/X; The common demoninator is fricas --squareFreePart factor denom Ů / squareFreePart factor numer Ů matrix Ξ(Ξ(numer retract(Ω/(𝐝.i*𝐝.j)),
Type: Matrix(SparseMultivariatePolynomial?(Integer,
Check "dimension" and the snake relations. fricas O:𝐋:= Ω / Ų
fricas test ( I ΩX ) / ( Ų I ) = I
Type: Boolean
fricas test ( ΩX I ) / ( I Ų ) = I
Type: Boolean
Cartan-Killing co-scalar fricas eval(Ω,
Definition 4Co-algebra Compute the "three-point" function and use it to define co-multiplication. fricas W:= (Y I) / Ų; fricas λ:= _ ( I ΩX ) / _ ( Y I ); fricas test ( ΩX I ) / ( I Y ) = λ
Type: Boolean
Cartan-Killing co-multiplication fricas eval(λ,
fricas test e / λ = ΩX
Type: Boolean
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