An electron is confined to a a square well of length L. What would be the length of the box such that the zero-point energy of the electron is equal to its rest mass energy, mₑ c² ? Express your answer in terms of the parameter λ_C=h / mₑ c, the 'Compton wavelength' of the electron.
a) λ_C/2
b) λ_C/4
c) λ_C
d) 2λ_C