  We consider the interaction of two weak probe fields of light with an atomic
ensemble coherently driven by two pairs of standing wave laser fields in a
tripod-type linkage scheme. The system is shown to exhibit a Dirac-like
spectrum for light-matter quasi-particles with multiple dark-states, termed
spinor slow-light polaritons (SSP). They posses an "effective speed of light"
given by the group-velocity of slow-light, and can be made massive by inducing
a small two-photon detuning. Control of the two-photon detuning can be used to
locally vary the mass including a sign flip. This allows e.g. the
implementation of the random-mass Dirac model for which localized zero-energy
(mid-gap) states exist with unsual long-range correlations.
