# Feynman’s path integral and an electron in a Penning trap

 P: 95 Last night the BBC repeated Brian Cox, A Night With the Stars (https://www.youtube.com/watch?v=HTU4CUhSmuw). At some point a calculation is done using a simplified version of Feynman’s path integral, where the mean time is estimated for a diamond to be found outside a small box: t>$\frac{x Δx m}{h}$ The box was not expected to be found empty then after several hundred billion times the age of the universe. But yet in 1973 it was found to be possible to capture a single electron in a Penning trap, and keep it there for over a week (http://www.iap.uni-bonn.de/lehre/ss0...Wineland73.pdf). So when I apply the formula above to the electron, I find that I only have to wait for about a second to have a reasonable chance to find it one meter outside of that trap. So why doesn’t this experiment invalidate Feynman’s formula?