Physlib.QuantumMechanics.OperatorAlgebra.Observables.Jordan
Jordan structure on observables
The observables of a complex C⋆-algebra carry the symmetrized product
a ⊙ b = 1/2 (ab + ba),
equivalently the real part of their algebra product.
This product is commutative and satisfies the Jordan identity. The type `JordanObservable A` equips the real vector space of observables with this product as its multiplication, giving a commutative Jordan algebra.
Jordan observables
`JordanObservable A` is the same underlying real vector space equipped with the symmetrized product as multiplication.
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Jordan product of observables
For two observables and in a complex -algebra , their Jordan product is defined as the symmetrized product , which corresponds to the real part of their algebraic product in .
Jordan product notation for observables
The notation represents the Jordan product of two observables and , defined by the symmetrized product .
Let be a complex -algebra. For any two observables (defined as self-adjoint elements where and ), their Jordan product is given by the symmetrized product where the multiplication and addition are those of the underlying algebra .
Commutativity of the Jordan product
For any two observables and in a complex -algebra , the Jordan product is commutative, satisfying . Here, the Jordan product is the symmetrized product defined by .
for observables
Let be a complex -algebra. For any observable (a self-adjoint element), the Jordan product of with itself is equal to its square in the algebra, i.e., .
Let be a complex -algebra. For any observables (self-adjoint elements), the Jordan product satisfies the distributive law .
Let be a complex -algebra. For any observables (self-adjoint elements) in , the Jordan product distributes over addition such that .
Let be a complex -algebra and let be observables in (self-adjoint elements such that and ). For any real scalar , the Jordan product satisfies the scalar homogeneity property:
Jordan Identity for Observables:
Let be a complex -algebra. For any observables (self-adjoint elements) , the Jordan product defined by satisfies the Jordan identity:
Jordan observables of an operator algebra
Let be an operator algebra. The type `JordanObservable A` is defined as the space of observables (self-adjoint elements such that ) equipped with the symmetrized Jordan product . It is a type synonym for `Observable A` used to provide the structure of a commutative Jordan algebra.
is an additive commutative group
For an operator algebra , the space of Jordan observables is an additive commutative group. This structure is inherited from the additive group structure of the space of observables .
-module structure on
For an operator algebra , the space of Jordan observables is a module over the real numbers . This vector space structure is inherited from the space of self-adjoint observables .
is a non-unital non-associative commutative ring
For an operator algebra , the space of Jordan observables is equipped with the structure of a non-unital non-associative commutative ring. The multiplication in this ring is the Jordan product, defined for any two observables as . This product is commutative () and satisfies the distributive laws and .
is a Commutative Jordan Algebra
Let be an operator algebra. The space of Jordan observables , consisting of the self-adjoint elements of equipped with the symmetrized product , is a commutative Jordan algebra. This means the product is commutative and satisfies the Jordan identity for all .
