  We theoretically propose an experimentally viable scheme to use an impurity
atom in an atomic Bose-Einstein condensate, in order to realize
condensed-matter analogs of quantum vacuum effects. In a suitable atomic level
configuration, the collisional interaction between the impurity atom and the
density fluctuations in the condensate can be tailored to closely reproduce the
electric-dipole coupling of quantum electrodynamics. By virtue of this analogy,
we recover and extend the paradigm of electromagnetic vacuum forces to the
domain of cold atoms, showing in particular the emergence, at supersonic atomic
speeds, of a novel power-law scaling of the Casimir force felt by the atomic
impurity, as well as the occurrence of a quantum frictional force, accompanied
by the Ginzburg emis- sion of Bogoliubov quanta. Observable consequences of
these quantum vacuum effects in realistic spectroscopic experiments are
discussed.
