Collective oscillations in spatially modulated exciton-polariton condensate arrays Andrey A. Tikhomirov, Oleg I. Kanakov, Boris L. Altshuler and Mikhail V. Ivanchenko Eur. Phys. J. B, 88 2 (2015) 37 Published online: 02 February 2015 DOI: 10.1140/epjb/e2014-50838-0