Equivalence of second-order sub-Poissonian statistics and fourth-order squeezing for intense light

We study the simultaneous occurrence of second-order sub-Poissonian photon statistics and fourth-order squeezing for the operator Xθ = X1cosθ+X2sinθ, in the displaced state , where the Hermitian operators X1,2 are defined by X1+i X2 = a, the annihilation operator, D(α) = exp(αa+−α*a) is the displacement operator, α = |α|ei θ and is the state of the weak optical field. We show that the two phenomena occur simultaneously when the amplitude |α| of the displacement is very large as compared to the amplitude of the weak optical field. We also propose a balanced homodyne method for detection of fourth-order squeezed light in the same fashion as that for normal squeezing.