Cavity QED with excitons in organic molecules and cold gases

Cavity Quantum Electrodynamics (CQED) has been extensively studied both theoretically and experimentally for many years now. A great deal of very successful experimental efforts have been devoted to single Rydberg atoms in a superconducting microwave resonator (micromaser) and ground state Alkali atoms in high-Q optical resonators. In both cases the strong coupling limit could be reached, where light matter coupling dominates the environmental decoherence and genuine quantum physics could be studied in a controlled way. Other implementations using solid state materials or ions followed and provided for genuine test ground of quantum information processing. The central aim of the present research proposal is to investigate new frontiers of cavity QED involving new types of matter, which are organic molecules and an optical lattice with a degenerate Bose gas. For the first candidate we aim to study organic molecules in a Cavity Quantum Electrodynamic set-up. Organic molecules have rich electronic and optical physical properties, and in particular very large dipole moments allowing for extraordinarily strong atom field coupling. Besides the fundamental study of light-matter interactions, this makes them very promising for applications in optoelectronic and quantum computing. Furthermore, organic molecules can serve as a significant source of nonlinear optical processes, anisotropic effects, and optical activities. In the second part, we aim to study a degenerate Bose gas loaded on an optical lattice within an optical cavity. The optical lattice is produced by external laser fields, while the cavity photons are treated quantum mechanically, and are taken to be close to resonance with the electronic excitation within the atoms of the Bose gas. Our goal is to develop a theory which enables a profound study of the system excitations, and mainly the effect of the different phases of the cold atom Bose gas in the optical lattice, which are the superfluid and Mott insulator phases, on the linear and nonlinear response to external optical fields. Although looking rather different at first sight, both models involve collective multiparticle excitations coupled to quantized field degrees of freedom of the cavity, which allows formally similar mathematical descriptions. We will investigate different possible experiments permit to extract considerable information about the system excitations. We seek to derive the linear optical spectra and photoluminescence of such systems, and also the nonlinear optical spectroscopy, e.g., pump-probe and four-wave- mixing experiments. In order to achieve the main proposal goals, we will use my background knowledge during my postdoctoral research in Scuola Normale Superiore di Pisa on organic microcavties, with the techniques and methods that were developed. Also the results of my Ph.D. research at the Technion-Israel Institute of Technology, about dissipations in coupled quantum systems, are of big importance here. The collaboration with the Group of Prof. Ritsch in the Institute for Theoretical Physics at the University of Innsbruck will be vital and productive for the present project, as they have big experience in Cavity Quantum Electrodynamics with atoms and ions, and also in Bose-Einstein Condensation of dilute Bose atom gas.