title: Spinor slow-light and dirac particles with variable mass.
abstract: 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 quasiparticles with multiple dark states, termed spinor slow-light polaritons. 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. Particularly, this allows the implementation of the random-mass Dirac model for which localized zero-energy (midgap) states exist with unusual long-range correlations.
authors.affiliation: Department of Physics and Research Center OPTIMAS, Technische Universität Kaiserslautern, Germany.
authors.forename: R G
authors.initials: RG
authors.lastname: Unanyan
authors.forename: J
authors.initials: J
authors.lastname: Otterbach
authors.forename: M
authors.initials: M
authors.lastname: Fleischhauer
authors.forename: J
authors.initials: J
authors.lastname: Ruseckas
authors.forename: V
authors.initials: V
authors.lastname: Kudriašov
authors.forename: G
authors.initials: G
authors.lastname: Juzeliūnas