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Q: Fachverband Quantenoptik und Photonik

Q 60: Quanteneffekte: Dekohärenz

Q 60.2: Talk

Friday, March 6, 2009, 10:45–11:00, VMP 6 HS-D

Non-destructive quantum state measurements — •Patrick Windpassinger, Daniel Oblak, Ulrich Hoff, Jürgen Appel, Niels Kjaergaard, and Eugene S. Polzik — QUANTOP, Niels Bohr Institute, Copenhagen, Denmark

Quantum non-demolition probing of a collective atomic (pseudo)-spin is a powerful instrument in quantum information processing and control. We present a method for non-destructive probing on the clock transition of laser-cooled, dipole trapped Cs atoms. The phase shift imposed by the atomic sample on an off-resonant probe laser beam is determined with a Mach-Zehnder interferometer.

The non-destructive probing also allows to follow online the evolution of the population difference of the Cs-atom clock states when subjected to microwave fields. This allows us to observe Rabi oscillations on the clock transition non-destructively over an extended period of time, which should yield a significant improvement of the signal-to-noise ratio compared to the traditional fluorescence-based destructive probing. The talk focusses specifically on the the effect of the probe-induced inhomogeneous light-shift and of the destructive probe-induced spontaneous photon scattering.

[1] P. Windpassinger et. al, Phys. Rev. Lett. 100, 103601 (2008)

[2] P. Windpassinger et. al, New J. Phys. 10, 053032 (2008)

[3] D. Oblak et. al, EPJ D 50, 67 (2008)