arXiv:0805.1948 · New Journal of Physics
Avalanches of Bose–Einstein condensates in leaking optical lattices
Gim Seng Ng, H Hennig, Ragnar Fleischmann, Tsampikos Kottos, Theo Geisel
Abstract
We study the decay of an atomic Bose–Einstein condensate (BEC) population N (τ) from the leaking boundaries of an optical lattice (OL). For a rescaled interatomic interaction strength Λ>Λ b , discrete breathers (DBs) are created that prevent the atoms from reaching the leaking boundaries. Collisions of other lattice excitations with the outermost DBs result in avalanches, i.e. steps in N (τ), which for a whole range of Λ-values follow a scale-free distribution P ( J =δ N )∼1/ J α . A theoretical analysis of the mixed phase space of the system indicates that 1<α<3, in agreement with our numerical findings.