Darmstadt 2008 – wissenschaftliches Programm

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Q: Fachverband Quantenoptik und Photonik

Q 22: Quantengase (Gitter II)

Q 22.4: Vortrag

Dienstag, 11. März 2008, 17:15–17:30, 1C

Counting atoms using interaction blockade in optical superlattices — •Ute Schnorrberger¹, Patrick Cheinet¹, Stefan Trotzky¹, Michael Feld^1,2, Simon Fölling³, and Immanuel Bloch¹ — ¹Institut für Physik der Universität Mainz — ²Fachbereich Physik der Technischen Universität Kaiserslautern — ³Harvard University, USA

We demonstrate the ability to accurately measure the occupation number statistics of ultra cold atoms loaded in a 3D optical lattice by means of an interaction blockade effect analogue to the Coulomb blockade observed in mesoscopic solid state systems.

We present results where a ⁸⁷Rb BEC was loaded in a 3D optical lattice either in the superfluid regime or in the Mott-Insulator regime. When ramping up an additional lattice on one axis with half the periodicity of the initial one we create an array of double wells. The bias, which means the tilt of the double wells, can be controlled by the relative phase between the two lattices forming this superlattice. Whenever the applied bias potential is high enough to compensate the interaction blockade, tunneling resonances occur. We observe these resonances by measuring the resulting atom numbers of each side of the double wells for the whole ensemble with different bias. The number distribution in the underlying long lattice is extracted from the resonance amplitudes measured for the ensemble of the double wells. This allows us to fully characterize the markedly different number distributions in the superfluid and Mott-Insulator regime.