  In large ensembles of identical atoms or spins, the interaction with a mode
of the electromagnetic radiation field concentrates in a single superradiant
degree of freedom with a collectively enhanced coupling. Given a controllable
inhomogeneous broadening, such ensembles may be used for multi-mode storage of
quantum states of the radiation field with applications in quantum
communication networks and quantum computers. In this paper we analyze how the
width and shape of the inhomogeneous broadening influence the collective
enhancement and the dynamics of the cavity-ensemble system with focus on the
consequences for the ensemble's applicability for quantum information
processing tasks.
