Effect Of The Driving Field's Noise On The Quantum Characteristic Of The Excited Atomic System

Resonance fluorescence and quantum entanglement are important not only for the basic understanding of quantum mechanics, but also for their practical applications.In this thesis, we study the quadrature squeezing spectra produced in the resonance fluorescence of a two-level atom driven by a strong coherent field and a weak amplitude-fluctuating field . For far-off-resonance and strong excitation, the resonance fluorescence exhibits two-mode squeezing around the Rabi sideband frequencies. Thus we have a source of two-mode squeezing that is very easily frequency tuned simply by adjusting the Rabi frequency of the atom. The presence of the strength of the stochastic process reduces the degree of squeezing obtainable. The quadrature squeezing spectra is also effected by the relative phase of the two fields.We also study the entanglement property between two two-level atoms interacting with a stochastic field. We analytically prove that when the correlation time κ~-1 of the stochastic field is very short compared to the radiative lifetime γ-1 of the atom, the steady-state entanglement between the two atoms can appear. The concurrence characterizing the entanglement degree has also been calculated by using Monte Carlo simulation. It is shown the correlation time has a strong effect on the entanglement. We also discuss the influence of the strength of the stochastic process on the entanglement.