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Atom optics is a well established field and the extension to the nonlinear regime naturally appears if interacting Bose Gases are utilized in the experiment. In this presentation an overview of the recent achievements in the direction of generation of entangled atomic states utilizing BEC will be given. Beside the adiabatic generation of spin squeezing in the external degrees of freedom, the diabatic generation of squeezed states in internal degrees of freedom will be present. For the latter case improved atom interferometry beyond the classical precision limit has been achieved explicitly. The results on generating suppressed relative atom number fluctuations utilizing spin changing collisions will also be discussed.
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