Consider the potential shown in the figure:
(x)A
R
where V(x) = 1D.
2mx^2
Estimate the lifetime of a particle with energy E in this potential. Take the potential at x = 0 to be +∞. Express your result in terms of the dimensionless ratio u = l/kR, where l > 1 and E = h^2/2m is the kinetic energy of the particle, which can be taken to be free inside the well, i.e. V(x) = 0 for 0 < x < R.