The story of the birth of quantum mechanics is often told, but not always correctly, in my opinion. Introductory quantum physics classes focus on the famous equation written by Erwin Schrödinger in 1926, which describes quantum waves. I think the emphasis on these waves has generated a confusion that persists today. The birth of quantum theory happened a year earlier, largely in the work of Max Born and his collaborators. And I like to draw attention to this point not just to give Born deserved credit, but also because I think the emphasis on Schrödinger’s waves is responsible for today’s confusion about what quantum phenomena tell us about reality.
Let me start from the beginning. It is often said that quantum physics arrived as a surprise at a time when physicists thought they had figured out all the basic laws of nature. There never was such a time. At the end of the 19th century, physicists were confused about plenty of basic things.
This article is part of a special series celebrating the 100th anniversary of the birth of quantum theory. Read more here.
This is why nobody paid much attention when, in October 1900, Max Planck came up with a simple but unjustified equation in trying to make sense of certain obscure experimental measurements of the electromagnetic radiation inside hot cavities. The equation was E = hν. It connects the energy (E) and the frequency (ν) of the radiation via a totally new constant (h), now known as Planck’s constant. This constant, we now know, sets the scale of quantum phenomena.
It was Albert Einstein,…
