Fundamental aspects of quantum optics : a dissertation

Abstract

The objective of this thesis is to investigate two fundamental problems of quantum optics: macroscopically distinguishable quantum superposition states and quantum chaos. After a brief introduction, Chapter II and Chapter III investigate the problem of superposition states. A method for generating the macroscopically distinguishable superposition states via single two-level atom dispersion was proposed by Savage et a/.[Opt.Lett. 15, 628(1990)]. In chapter II, an extension of this model to a three-level atom is investigated and the result shows that the superposition state can be obtained from the three-level model sytem in the dispersive limit. In chapter III, S ’ the effect of the atomic linewidth is considered. If the atomic linewidth is included, there will be two contradictory conditions for the generation of distinguishable superpositon states. This shows that the atomic linewidth prevents the formation of macroscopically distinguishable superpositon states by the proposed method. From chapter IV to chapter VI, we investigate the transition from a dissipative quantum system to a classically chaotic system. Specifically, wre apply the method of quantum trajectories to the case of optical second harmonic generation. In chapter V, the Q function is obtained numerically by this method and found to agree with the results obtained by solving the master equation. In chapter VI, the field amplitudes and mean photon number associated with a single quantum trajectory are investigated. The results show that the trajectory becomes more classical and the configuration of the classical strange attractor is approached as the field strength is increased. This is because the mean values of operator products factorize into products of mean values in the classical limit. Show more