Black-hole lasing in coherently coupled two-component atomic condensates

We study theoretically the black-hole lasing phenomenon in a flowing one-dimensional, coherently coupled two-component atomic Bose-Einstein condensate whose constituent atoms interact via a spin-dependent s-wave contact interaction. We show by a numerical analysis the onset of the dynamical instability in the spin branch of the excitations, once a finite supersonic region is created in this branch. We study both a spatially homogeneous geometry and a harmonically trapped condensate. Experimental advantages of the two-component configuration are pointed out, with an eye towards studies of backreaction phenomena.