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Q: Quantenoptik und Photonik

Q 14: Quantengase III

Q 14.4: Vortrag

Montag, 13. März 2006, 17:45–18:00, HVI

Density distribution and compressibility of a confined Mott Insulator — •Simon Fölling, Artur Widera, Fabrice Gerbier, Torben Müller, Olaf Mandel, and Immanuel Bloch — Institut für Physik der Universität Mainz, 55099 Mainz

We measure the density distribution of an atomic sample in the Mott insulating state of a periodic lattice potential in a variable external confinement. Due to this variable harmonic confinement at a given lattice depth, the in-trap atom density and therefore the average lattice filling factor can be changed for a constant total number of ⁸⁷Rb atoms . The global profile of the resulting atom distribution in the trap is determined using microwave spectroscopy in a gradient field, while the on-site atom number distribution is probed using coherent spin-changing collisions on multiply occupied sites [1]. The formation of regions with lattice site occupancies n>1 is shown, in accordance with the predictions for the atomic MI state [2]. We investigate the shell structure formation and the associated change in compressibility on the transition from a singly- to a doubly-occupied Mott insulator.

[1] F. Gerbier et al., cond-mat/0511080 (2005)

[2] D. Jaksch et al., Phys. Rev. Lett. 81, 3108 (1998)