RKKY interactions in Anderson insulator

Clare C. Yu, Steven R. White

Benjamin Deissler, Chiara D’Errico, M. Fattori +5 more

Reinhold Egger, Herbert Schoeller

Philippe Jacquod

Yukihiro Shimizu

The single particle excitation spectrum of the periodic Anderson model in two dimensions is calculated by using the dynamical cluster approximation (DCA). The DCA method is an extention of the dynamical mean field approximation, that is, the short range inter-site correlations are restored by considering the cluster. For the half filling model there is no sharp coherence peak at the Fermi level due to the anti-ferromagnetic Ruderman–Kittel–Kasuya–Yosida (RKKY)-like interaction. When the filling of the conduction electron band is small, there is a sharp coherence peak. It can be explaind that the effect of the RKKY-like interaction is weaker than that for the half filling model or the RKKY-like interaction changes to the ferromagnetic one. For the intermediate filling model the intensity of the coherence peak becomes very small.

Conor Jackson, Bernd Braunecker

Fermi-edge singularity and Anderson's orthogonality catastrophe are paradigmatic examples of non-equilibrium many-body physics in conductors, appearing after a quench is created by the sudden change of a localized potential. We investigate if the signal carried by the quench can be used to transmit a long ranged interaction, reminiscent of the RKKY interaction, but with the inclusion of the full many-body propagation over space and time. We calculate the response of a conductor to two quenches induced by localized states at different times and locations. We show that building up and maintaining coherence between the localized states is possible only with finely tuned interaction between the localized states and the conductor. This puts bounds to the use of time controlled RKKY type interactions and may limit the speed at which some quantum gates could operate.