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Fractal Universality in Near-Threshold Magnetic Lanthanide Dimers



Eite Tiesinga, Constantinos Makrides, Ming Li, Svetlana Kotochigova


Ergodic quantum systems are often quite alike whereas non-ergodic, fractal systems are unique and display characteristic properties. In this paper we explore one of such fractal systems, weakly-bound dysprosium lanthanide molecules in an external magnetic field. As recently shown colliding ultracold magnetic dysprosium atoms display a {\it soft} chaotic behavior with a small degree of disorder. Here, we broaden this classification by investigating the generalized inverse participation ratio (GIPR) and fractal dimensions for large sets of molecular wavefunctions. Our exact close-coupling simulations reveal a dynamic phase transition from partially localized states to totally delocalized states and universality in its distribution by increasing the magnetic field strength to only a hundred Gau ss (or 10 mT). Finally, we prove the existence of nonergodic delocalized phase in the system and explained the violation of ergodicity by strong coupling between near-threshold molecular states and the nearby continuum.
Science Advances


quantum chaos, Feshbach resonances, ultracold atoms


Tiesinga, E. , Makrides, C. , Li, M. and Kotochigova, S. (2018), Fractal Universality in Near-Threshold Magnetic Lanthanide Dimers, Science Advances, [online], (Accessed May 26, 2024)


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Created February 16, 2018, Updated November 10, 2018