  A Lie-algebraic approach successfully used to describe one-dimensional Bloch
oscillations in a tight-binding approximation is extended to two dimensions.
This extension has the same algebraic structure as the one-dimensional case
while the dynamics shows a much richer behaviour. The Bloch oscillations are
discussed using analytical expressions for expectation values and widths of the
operators of the algebra. It is shown under which conditions the oscillations
survive in two dimensions and the centre of mass of a wave packet shows a
Lissajous like motion. In contrast to the one-dimensional case, a wavepacket
shows systematic dispersion that depends on the direction of the field and the
dispersion relation of the field free system.

Quantum Physics