Time factorization of the higher-order intensity correlation functions in the theory of resonance fluorescence

Abstract

The intensity correlation functions Tr{ρ(0)s⁺(t)s⁺(t+T₁)... s⁺(t+Σ_i=1ⁿT_i)s^- (t+Σ_i=1ⁿT_i)... s^-(t+T₁)s^-(t)} associated with a two-level atom undergoing Markovian dynamics [s^± (t) being the spin-½ operators for the atom] are shown to factorize in the form f(t)Π _i=1ⁿg(T_i) with f(t) [g(t)] giving the probability of finding the atom in the excited state when initially it is in the state ρ(0) [ground state].