We find time evolution law of negative binomial optical field in diffusion channel. We reveal that by adjusting the diffusion parameter, photon number can controlled. Therefore, the diffusion process can be considered a quantum controlling scheme through photon addition.
According to the combinational binomial-negative-binomial distribution, we propose a binomial-negative-binomial combinational optical field state, which can be generated in the process of a Fock state |m>m| passing through a quantum-mechanical diffusion channel. We derive the second-order coherence degree formula, g(2)(t) =2-((m2+m)/(m+κt2)), which is the diffusion constant. We find that in the process of the Fock state undergoing quantum diffusion and becoming classical, the corresponding photon statistics evolves from sub-Poissonian distribution to Poisson distribution and finally goes to a chaotic state. We also find that the more photons in the initial Fock state, the longer time is needed for quantum decoherence.
Using negative entropy method,the quantum entanglement characteristics of the system of binomial optical field interacting with moving atom were studied.The influences of the atomic initial state,field-mode structure parameter,maximum photon number of binomial field,coefficient of binomial field,transition photon number and detuning were discussed.The results show that the value of entanglement degree of the system appears regular evolution and entanglement sudden death(ESD) phenomenon when atomic motion was considered.The increasing of the field-mode structure parameter shortens the period of the entanglement and results in a slight decreasing of amplitude.The atomic initial state affects the entanglement degree of the system.When the atomic initial state tends to pure state,the entanglement degree of the system is larger relatively.With increase of the maximum photon number of binomial field,the value of the entanglement degree of system becomes small,but the period for regular evolution is almost unchanged.When the field is in the middle states,the entanglement degree is smaller relatively.With the increase of the transition photon number,the value of the entanglement degree of the system becomes larger,the period of the oscillation becomes shorter,meanwhile the oscillation of the system becomes faster and faster.With the detuning increasing,the entanglement becomes small.