  We derive the uncertainty principle for a Dirac fermion in a torsion field
obeying the Hehl-Datta (HD) equation. We first discuss that there should be a
correction factor to the Heisenberg uncertainty principle (HUP) when torsional
effects are taken into consideration. We then derive the uncertainty relation
from a solitary wave solution of the HD equation in 1+1 dimensions. We find
that the results agree with the generalized uncertainty principle (GUP). We
then introduce the unified length scale $L_{CS}$ (which unifies Compton
wavelength and Schwarzschild radius) into the HD equation and see how the
probability density of the solution transforms for particles of different
masses.
