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Start date: 01 May 2009, End date: 31 Aug 2010 PROJECT  FINISHED 

The physics of interacting one-dimensional systems is very different from that of ordinary three-dimensional configurations. In systems where the dynamics is constrained to only one dimension, interactions play a special role since particles can not avoid each other. As a result, the behaviour of 1D systems turns out to be very peculiar and often counter-intuitive, making them very interesting to study. For example, interacting 1D bosons have the fascinating property to “fermionize” as strong interactions mimic the Pauli exclusion principle. It has been proposed that such one-dimensional systems could be obtained by loading degenerate atomic gases in optical dipole potentials. The scientific interest for the realization of strongly correlated systems goes beyond the field of cold atoms as it might shed new light on long-standing issues in condensed matter physics. Some first experiments have been realized to manipulate such strongly interacting 1D Bose gases. Here, we propose to use optical dipole potentials (a red-detuned 2D lattice and a blue-detuned beam controlling the longitudinal curvature) to create strongly correlated degenerate 1D Bose gases. Such a setup will allow us to continuously tune our 1D gases from the mean-field regime to close to a “fermionized” Bose gas (Tonks-Girardeau regime). We plan to implement a Bragg spectroscopy scheme with a tunable angle and to make use of the noise correlation technic to quantitatively characterize the correlations in the 1D gases, including the spatial extent of correlation functions and their scaling with the strengh of interactions. In addition we propose to study metal-insulator quantum phase transitions induced by the presence of an optical lattice (Mott transition) or a disordered potential (Bose Glass phase) in the strongly interacting regime. A clear identification of these new insulating quantum phases should be provided by the use of the Bragg spectroscopy and noise correlation technics.
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