X iv : c on d - m at / 9 70 80 28 v 1 4 A ug 1 99 7 Local polariton states in impure ionic crystals

ar X iv : c on d - m at / 9 70 80 28 v 2 6 J an 1 99 8 Local polariton states in impure ionic crystals

We consider the dynamics of an ionic crystal with a single impurity in the vicinity of the polariton resonance. We show that if the polariton spectrum of the host crystal allows for a gap between polariton branches, the defect gives rise to a novel kind of local states with frequencies within the gap. Despite the atomic size of the impurity we find that new local states are predominated by long...

ar X iv : c on d - m at / 9 70 80 30 v 1 [ co nd - m at . s up r - co n ] 5 A ug 1 99 7 1

ar X iv : c on d - m at / 9 70 80 19 v 1 4 A ug 1 99 7 Surface Phason – Polaritons in Charge Density Wave Films

The coupled non–radiative excitations of the electromagnetic field and pha-sons in films with a quasi one–dimensional charge density wave (CDW) are evaluated for P–polarization and CDW conducting axis inside the film. The prominent features are two surface phason–polariton branches extending from the CDW pinning frequency to the frequency of the longitudinal optical phason. These surface phason...

ar X iv : c on d - m at / 9 70 81 77 v 1 2 2 A ug 1 99 7 Theory of Photoemission from the Copper Oxide Material

A mean-field theory which satisfying the electron on-site local constraint in the relevant regime of density for the high temperature superconductors is developed. electron density of states of copper oxide materials are discussed, and the results are qualitative consistent with the numerical simulations.

ar X iv : h ep - l at / 9 70 80 09 v 1 1 5 A ug 1 99 7 SCREENING LENGTHS IN SU

We discuss the calculation of electric and magnetic screening masses in SU(2) gauge theory. The temperature dependence of these masses obtained from the long-distance behaviour of spatial correlation functions has been analyzed for temperatures up to 10 4 Tc.