Subradianz und Materie-Licht-Verschränkung mit Bose-Einstein-Kondensaten in optischen Ringresonatoren

01/10/2015 to 01/10/2018

The combination of cold atoms and high finesse optical resonators offers an almost ideal model system for investigating fundamental aspects of atom light interaction. In the presented project, a ring resonator will be developed with a line width below the single photon recoil shift of the rubidium D2-line. By means of such a recoil resolving resonator, collective subradiant states will be generated and investigated. As second topic, resonator induced entanglement between atoms and light will be studied for various pump scenarios. For this purpose, a single atom detector will be developed which allows for observing the (2)g-correlation functions for subradiant states. The detector will also be used to study the quantum fluctuations near the CARL- threshold: Above a critical pump intensity photon scattering is suddenly increases while the atoms are strongly accelerated along the direction of the pump beam. Near this threshold, atom-light-entanglement is predicted which leads to non-classical cross-correlation functions. In particular, the question should be answered to which extend the threshold can be interpreted as a quantum phase transition.