  Various quantum theories of gravity predict the existence of a minimal
measurable length. In this paper, we study effects of the minimal length on the
motion of a particle in the Rindler space under a harmonic potential. This toy
model captures key features of particle dynamics near a black hole horizon, and
allows us to make three observations. First, we find that the chaotic behavior
is stronger with the increases of the minimal length effects, which manifests
that the maximum Lyapunov characteristic exponents mostly grow, and the KAM
curves on Poincar\'{e} surfaces of section tend to disintegrate into chaotic
layers. Second, in the presence of the minimal length effects, it can take a
finite amount of Rindler time for a particle to cross the Rindler horizon,
which implies a shorter scrambling time of black holes. Finally, it shows that
some Lyapunov characteristic exponents can be greater than the surface gravity
of the horizon, violating the recently conjectured universal upper bound. In
short, our results reveal that quantum gravity effects may make black holes
prone to more chaos and faster scrambling.
