Institution: | (1) Department of Solid State Physics, Moscow Engineering Physics Institute, Kashirskoe Sh. 31, Moscow, 115409, Russia;(2) Department of Mathematics, University of Arizona, 617 North Santa Rita Avenue, 85721, Tucson, Arizona, USA;(3) L.D. Landau Institute for Theoretical Physics, 2 Kosygin St., Moscow, 119334, Russia |