  We consider tachyonic braneworld with a bulk cosmological constant and
investigate a configurational entropy of various magnitudes of scale factor. It
is found that for a bulk negative/zero cosmological constant, the
configurational entropy has a global minimum when the magnitude of scale factor
reaches the critical value. This result seems to have intriguing implications
such that an accelerated rate of the universe and cosmological inflation rate
for radiation/matter domination are able to be determined by such critical
value. We also find that the configurational entropy almost monotonically
decreases for a bulk positive cosmological constant as the magnitude of scale
factor grows up. We find an exact solution of tachyonic braneworld in a bulk de
Sitter space. It is shown that such system under scalar perturbations is stable
for some constraint relation. Furthermore, we also find that tachyonic
braneworld model with a bulk negative/zero cosmological constant is always
stable under scalar perturbations.
