Hamburg 2009 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 30: Poster II

Q 30.25: Poster

Tuesday, March 3, 2009, 16:30–19:00, VMP 9 Poster

Quantum Jumps and Continuous Spin Measurement in a Strongly Coupled Atom-Cavity System — Wolfgang Alt, Tobias Kampschulte, Mkrtych Khudaverdyan, Sebastian Reick, •Alexander Thobe, Artur Widera, and Dieter Meschede — Institut für Angewandte Physik, Universität Bonn, Wegelerstr. 8, 53115 Bonn, Germany

In our experiment, we study the coherent interaction between a predetermined, small number of atoms and the light field inside a high-finesse optical resonator in the strong coupling regime. To this end, we trap caesium atoms in a high-gradient magneto-optical trap and transport them into the center of the resonator mode, using an optical dipole trap [1].

By monitoring the transmission of a probe laser resonant with the cavity, we are able to measure the spin state of a single atom in 2ms without changing it. Continuous observation reveals quantum jumps between the two hyperfine states of caesium. Utilizing this non-destructive detection method, we record the interaction induced normal mode splitting of the atom-cavity system by probing the atomic state. We further demonstrate conditional dynamics of the internal states of multiple atoms, simultaneously coupled to the resonator field. Our non-destructive state detection is the first step towards a quantum non-demolition measurement of the atomic spin as is required for probabilistic atom-atom entanglement schemes.

[1] M. Khudaverdyan et al., New J. Phys. 10, 073023 (2008).