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Localization in disordered bosonic insulators with strong, short-range interactions
Arvid Kingl (LMU)
12.10.2012 at 14:00
In the talk, I will present results of my thesis which addresses properties of strongly localized bosonic insulators. A recent interest to the bosonic insulators was stipulated
by their anomalous magnetoresistance at low temperatures. I will review relevant experiments and recent theoretical results which were obtained by using a locator expansion applied to a toy-model for the hard-core bosons. In my thesis, I have considered the disordered Bose-Hubbard model and have developed the locator expansion in terms of Hubbard operators and their correlation functions. This method allows one to study the bosons with strong, but finite short-range interactions U. The leading 1/U correction to the localization radius has been calculated. It has been shown that a decrease in the interaction strength enhances delocalization. Based on this result, a maximum
in the localization length as a function of U has been predicted at a transient between the hard-core- and the weakly-interacting regimes. The maxima is expected to occur at U ~ W, W being the disorder strength, and its existence can be directly tested in experiments with cold gases in disordered potentials.
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