  We have studied the physical processes responsible for the spin -flip in GaAs
quantum dots. We have calculated the rates for different mechanisms which are
related to spin-orbit coupling and cause a spin-flip during the inelastic
relaxation of the electron in the dot both with and without a magnetic field.
We have shown that the zero-dimensional character of the problem when electron
wave functions are localized in all directions leads to freezing out of the
most effective spin-flip mechanisms related to the absence of the inversion
centers in the elementary crystal cell and at the heterointerface and, as a
result, to unusually low spin-flip rates.
