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In quantum field theory, if V is a real vector space equipped with a nonsingular real antisymmetric bilinear form (,) (i.e. a symplectic vector space), the unital *-algebra generated by elements of V subject to the relations

fg-gf=i(f,g)
f*=f

for any f, g in V is called the canonical commutation relations (CCR) algebra. The uniqueness of the representations of this algebra when V is finite dimensional is discussed in the Stone-von Neumann theorem.

There is also a corresponding unital C*-algebra, often referred to as the Weyl form of the algebra, generated by eif subject to

e^{ic_1 f}e^{ic_2 f}=e^{i(c_1+c_2) f}
e^{if}e^{ig}=e^{-i(f,g)}e^{ig}e^{if}
(eif)*=e-if

for real numbers c1, c2.

If V is equipped with a nonsingular real symmetric bilinear form (,) instead, the unital *-algebra generated by the elements of V subject to the relations

fg+gf=(f,g)
f*=f

for any f, g in V is called the canonical anticommutation relations (CAR) algebra.

If V is a real Z2-graded vector space equipped with a nonsingular antisymmetric bilinear superform (,) (i.e. (g,f)=-(-1)|f||g|(g,f) ) such that (f,g) is real if either f or g is an even element and imaginary if both of them are odd, the unital *-algebra generated by the elements of V subject to the relations

fg-(-1)^{|f||g|}gf=i(f,g)
f*=f, g*=g

for any two pure elements f, g in V is the obvious super generalization which unifies CCRs with CARs.

See also


Quantum field theoryfunctional analysis

 

This article is licensed under the GNU Free Documentation License. It uses material from the "CCR and CAR algebras".

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