Polarons: from single polaron to short scale phase separation

Short review of the phase separation in the system of charged polarons.Comment: 18 pages 5 figures, to be published in Polarons in Advanced Materials, Ed. A. S. Alexandrov (Canopus/Springer Publishing, Bristol) (2007

Excitations and phase segregation in a two component Bose-Einstein condensate

Bogoliubov-de Gennes (BdG) equations and the excitation spectrum of a two-component Bose-Einstein condensate (BEC) are derived with an arbitrary interaction between bosons, including long-range and short range forces. The nonconverting BEC mixture segregates into two phases for some two-body interactions. Gross-Pitaevskii (GP) equations are solved for the phase segregated BEC. A possibility of boundary-surface and other localised excitations is studied.Comment: 9 pages, 2 figure