a Study of the Quantum Nature of Light: Macroscopic Quantum Jumps from a Two-Atom System, Photon Statistics, and Light Propagation

Kazunari Yamada, P. R. Berman

Charles A. McDermott

We first use the quantum method to replicate the well-known results of a single atom relaxing, whilst demonstrating the intuitive picture it provides for dissipative dynamics. By use of individual "quantum trajectories", the method allows for simulation of systems inaccessible to ensemble treatments. This is shown by replicating resonance fluorescence, allowing us to concurrently demonstrate the method's facilitation of calculating photon statistics by the creation of discrete photon streams. To analyse these, we solidify the theoretical basis for, and implement, a computational method of calculating second-order coherence functions. A process by which to model interacting two-atom systems to allow for computation with the quantum jump method is then developed. Using this, we demonstrate cooperative effects leading to greatly modified emission spectra, before investigating the decoupling of states from dissipative and coherent interactions. Here, we find the novel insight provided by the quantum jump method both births and provides the tools with which to begin an investigation into the occurrence of macroscopic jumps and the formation of macroscopic dark periods in a system of two two-level dipole-dipole coupled atoms.

Muhammad Waseem, Faizan-e-Ilahi, Muhammad Sabieh Anwar

Juha Javanainen

We compare the statistics of photon counts of the light scattered by a laser-driven two-level system weakly coupled to a third metastable state with the statistics of a dichotomic Markov process. The fluorescence is found to turn abrubtly off and on, as if the atom executed quantum jumps to and from the metastable state. Moreover, the jumping nature of the fluorescence over long time scales survives even though the atom cannot be treated with rate theory and the picture of instantaneous quantum jumps is not strictly justified.

Antonín Luk¿, Vlasta Peřinová

Kazunari Yamada, P. R. Berman

We analyze the macroscopic quantum jumps (sudden interruptions in the fluorescence on a macroscopic time scale) that are produced when a pair of two-level atoms separated by a distance d is irradiated by a strong laser having wavelength ${\ensuremath{\lambda}}_{0}$, with ${\ensuremath{\lambda}}_{0}$\ensuremath{\gg}d. Included in the analysis is the dipole-dipole coupling of the atoms, the ac Stark effect, and the role played by a term that is present in the atom-laser field interaction Hamiltonian when k\ensuremath{\cdot}d\ensuremath{\ne}0 (k is the wave vector of the laser field and d is the vector connecting the two atoms). Our treatment is based on frequency-resolved delay functions, an extension of a concept developed by Reynaud, Dalibard, and Cohen-Tannoudji [IEEE J. Quantum Electron. 24, 1395 (1988)], which is shown to be useful to study frequency-resolved photon statistics. As examples, we study the statistics of the fluorescence produced by the two-atom system as well as those in the components of the fluorescent triplet produced by a single two-level atom.