  We study the decoherence speed limit (DSL) of a single impurity atom immersed
in a Bose-Einsteincondensed (BEC) reservoir when the impurity atom is in a
double-well potential. We demonstrate how the DSL of the impurity atom can be
manipulated by engineering the BEC reservoir and the impurity potential within
experimentally realistic limits. We show that the DSL can be controlled by
changing key parameters such as the condensate scattering length, the effective
dimension of the BEC reservoir, and the spatial configuration of the
double-well potential imposed on the impurity. We uncover the physical
mechanisms of controlling the DSL at root of the spectral density of the BEC
reservoir.
