Higher-Order Sub-Poissonian statistics in interaction of two two-level atoms with a single mode coherent radiation

In the present paper we study higher-order sub-Poissonian photon statistics in interaction of a single mode radiation initially in the coherent state Ŧα〉 with an assembly of two excited two-level atoms using the Hamiltonian, H=ω(a⁺a+S_z)+g(aS₊+a⁺S.), in the natural system of units. Here, α=|α|e^iθ_α, a is the annihilation operator for radiation, S_z and S_± are the collective Dicke operators, g is the coupling constant, ω is the energy of the photons and the energy difference between the two atomic levels. We solve it exactly and conclude that higher-order sub-Poissonian photon statistics can be obtained for an arbitrary order by choosing suitably the square root of mean photon number |α| of the coherent radiation and coupling time gt. Variations of higher-order sub-Poissonian photon statistics with parameters |α| and gt have also been discussed.