Q

Q(α) representation The representation of the density operator ρ in terms of matrix elements with respect to the pure coherent state |α >, i.e., Q(α, α∗) = <α|ρ|α>

π . The normal-

ization of the density operator to unity, together with the completeness of the coherent states, implies that

∫ Q(α, α∗)d2α = 1.