One of the quietest revolutions of our current century has been the entry of quantum mechanics into our everyday technology. It used to be that quantum effects were confined to physics laboratories and delicate experiments. But modern technology increasingly relies on quantum mechanics for its basic operation, and the importance of quantum effects will only grow in the decades to come. As such, physicist Miguel F. Morales has taken on the herculean task of explaining quantum mechanics to the rest of us laymen in this seven-part series ( no math , we promise). Below is the second story in the series, but you can always find the starting story here .

Welcome back for our second guided walk into the quantum mechanical woods! Last week, we saw how particles move like waves and hit like particles and how a single particle takes multiple paths. While surprising, this is a well-explored area of quantum mechanics—it is on the paved nature path around the visitor’s center.

This week I’d like to get off the paved trail and go a bit deeper into the woods in order to talk about how particles meld and combine while in motion. This is a topic that is usually reserved for physics majors; it's rarely discussed in popular articles. But the payoff is understanding how precision lidar works and getting to see one of the great inventions making it out of the lab, the optical comb. So let's go get our (quantum) hiking boots a little dirty—it'll be worth it.