Spatial period doubling in Bose-Einstein condensates in an optical lattice

摘要: We demonstrate that there exist stationary states of Bose-Einstein condensates in an optical lattice do not satisfy the usual Bloch periodicity condition. Using discrete model appropriate to tight-binding limit we determine energy bands for period-doubled a one-dimensional lattice. In complementary approach calculate band structure from Gross-Pitaevskii equation, considering both form and which have period equal twice show onset dynamical instability coincides with occurrence same energy. The are shown be related periodic trains solitons.