Deterministic production of free-propagating Fock states of programmable   photon number from a single atom-cavity system
  We propose a mechanism for producing Fock states on demand leaking from a single mode optical cavity interacting with a single atom and a laser pulse. The number of photons can be chosen, as it is determined by the Zeeman substructure of the ground state of the atom and its initial state. The deterministic generation of a free-propagating Fock state of $1\leq n\leq2F$ photons is achieved, when a circularly polarized laser pulse completely transfers the atomic population between Zeeman sublevels of the ground hyperfine state $F$ through far-detuned Raman scattering thus producing linearly polarized cavity photons. We describe analytically the evolution of optical field taking into account the spontaneous losses and the cavity damping. We demonstrate the possibility of production of Fock-state with different numbers of photons by using different transitions of the same atom. We show also that this technique provides a deterministic source of a train of identical multiphoton Fock-states, if a sequence of left- and right-circularly polarized laser pulses is applied. The resulting states have potential applications in quantum computation and simulation. 
A. Gogyan, S. Guerin, C. Leroy, Yu. Malakyan
quant-ph physics.atom-ph