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Master Dissertation

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The Wightman Axioms.<br />

Axiom 1 (quantum field) The operators φ1(f), . . . , φn(f) are given<br />

for each C ∞ -function f with compact support on the Minkowski space<br />

R 4 . Each φj(f) and its Hermitian conjugate operator φj(f) ∗ are defined<br />

at least on a common dense linear subset D of the Hilbert space H and<br />

D satisfies<br />

φj(f)D ⊂ D, φj(f) ∗ D ⊂ D,<br />

for any f and j = 1, . . . , n. For any Φ, Ψ ∈ D,<br />

is a complex valued distribution.<br />

f ↦→ (Φ, φj(f)Ψ),<br />

Axiom 2 (relativistic symmetry) On H there exists a unitary repre-<br />

sentation U(a, A) of ˜ P ↑<br />

+ (a ∈ R4 , A ∈ SL(2, C)), satisfying U(a, A)D =<br />

D (invariance of the common domain of the fields).<br />

U(a, A)φj(f)U(a, A) ∗ = S(A −1 )jkφk(f (a,A))<br />

f (a,A)(x) = f(Λ(A) −1 (x − a)),<br />

where the matrix (S(A)j,k) is an n-dimensional representation of A ∈<br />

SL(2C).<br />

Axiom 3 (local commutativity) If the support of f and g is spacelike<br />

separated, then for any vector Φ ∈ D<br />

[φj(f) (∗) , φk(g) (∗) ]±Φ = 0,<br />

where (∗) indicates that the equation holds for any choice.<br />

Axiom 4 (vacuum state) There exists a vector |0〉 in D satisfying the<br />

following conditions:<br />

(i) (Ua, A)|0〉 = |0〉 (invariance).<br />

(ii) The set of all vectors obtained by acting an arbitrary polynomial<br />

P of the fields on |0〉 is dense in H (cyclicity).<br />

(iii) The Spectrum of the translation group U(a, 1) on |0〉 ⊥ is contained<br />

in<br />

V m = {p|(p, p) ≥ m 2 , p 0 > 0} (m > 0)<br />

(Spectrum condition).<br />

26

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