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We investigate the electronic dynamics of an atom, whose bounded electrons interact with electrons in two environmental baths. Focusing on the spin degree of freedom, we study equilibration and transport effects in the atomic subsystem. We include an effective crystal field, which arises from the substrate the atom is living on and gives the magnetic component of the atom an easy axis for alignment. First, we determine stationary states using a quantum master equation and compare our results to a semi-classical approach using a rate equation. This allows us to understand the limits of the semi-classical approach and the correction from our complete quantum mechanical consideration. Second, we consider a spin-polarized electron reservoir that breaks the rotational symmetry around the quantization axis. This system requires to consider the complete density operator of the atom, where its knowledge allows to calculate magnetization dynamics and transport properties on
an equal footing. We discuss the electron transport through the atom by especially focusing on the non-linear influence of the spin torque effect due to exchange interaction.
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