Direct observation of a sub-Poissonian number distribution of atoms in an optical lattice.

We report single-site resolution in a lattice with tunneling between sites, allowing for an in situ study of stochastic losses. The ratio of the loss rate to the tunneling rate is seen to determine the number fluctuations, and the overall profile of the lattice. Sub-Poissonian number fluctuations are observed.

Spreading for the generalized nonlinear Schrödinger equation with disorder.

The dynamics of an initially localized wave packet is studied for the generalized nonlinear Schrödinger equation with a random potential, where the nonlinear term is beta|psi|ppsi and p is arbitrary. Mainly short times for which the numerical calculations can be performed accurately are considered. Long time calculations are presented as well.