The US Penny as a Quantum Object

Ever wonder if quantum effects influence everyday objects? Here's a very rigorous analysis of how often either thermal vibrations or quantum tunneling are likely to topple a penny balanced on edge.

Turns out to be . . . seldom! (And that's perhaps the most flagrant understatement I've ever made...)

I can just barely follow the calculations, but mathematicians out there may find this musing by Nick Herbert to be intriguing.