Second Lesson: Quanta

In response to The Daily Post's writing prompt: "Trick Questions."

Carlo Revelli (2015) Seven Brief Lessons on Physics, translated by Simon Carnell and Erica Segree.

If Isaac Newton is the father of physics, Albert Einstein is the mother, but he didn’t love all his children equally. Remember before Einstein, physics was spread out like a dirty nappy between subjects as diverse as Mathematics, Philosophy and the industry leader, Chemistry, in universities and colleges. A fresh-faced Richard Feynman after leaving the Manhattan Project, for example, found himself teaching at Cal Tech. He was the Physics’ department. The atom bomb changed everything, but before the atom bomb, quantum theory (or quantum mechanics) changed everything we know, or think we know, about atoms. Einstein’s theory of gravity, space and time wrapped reality up in a big red bow. Quantum mechanics picked it apart and introduced uncertainty into equations. No one was quite sure how it worked, but quantum mechanics did work. Nowadays, for example, quantum computers exist. Birds navigate from continent to continent by 'seeing' the curve of space/time.  Einstein before he died was trying to reconcile the known and the unknown. His theory of everything was championing the god of objectivity in science. And Niels Bohr, whose ongoing dialogue with Einstein enriched science, suggested at a subatomic level the devil of subjectivity played a part. Before he died Bohr had a photograph taken, in the background, a blackboard in his study. The drawing on it is a ‘light filled box’ something Einstein conceived as a thought experiment.

‘Imagine a box filled with light, from which we allow a single photon to escape for an instant…’

Photon from phos/phot ‘light’, but light is both singular and pleural. One cannot be separated from the other.

But that is exactly what Max Planck did. He imagined a hot box. In it an electric field in equilibrium. His genius was suggesting that the energy of this field could be broken down into quanta, packets or lumps of energy. Light, which travelled at a uniform speed through space, in relation to the energy expended in creation, was somehow at a subatomic level, lumpy. It made no sense, but made perfect sense. Einstein confirmed Planck’s hypothesis was correct.

Bohr’s genius was the nowadays clichéd quantum leap of gaining the philosopher’s stone, without quite knowing how it worked. He described how electrons gain and lose the energy of light (that quantum leap) from one oscillating orbit to another and how Mendeleev’s periodic table of how everything remains the same, but is different, could be best understood.

A fellow German physicist, Werner Heisenberg, put a new spin on it by suggesting, at a subatomic level, electrons do not always exist. Objective reality therefore does not exist. An apple, for example, either exist, or it does not. But Heisenberg suggested we did not to follow that strict dichotomy. We could calculate the probability of an electron existing, but only when colliding with something else and making a quantum leap. Before and after, is not measureable, and in the same way, when I’m offline I no longer exist and have no place in the world.

Rovelli puts it very succinctly: ‘It’s as if God had not designed reality with a line that was heavily scored, but just dotted with a faint outline.’

Possibility and probability replace all the old certainties. But like alchemists of old not only were electrons called into being when observed jumping from one random state to another, but the subjective element of looking or measuring could not be teased from cause and effect. I, for example, only exist online when you look at me. I don’t exist otherwise. Or I may exist, but you can’t prove it. And if you try and look at me offline you can no longer see me online. The real and unreal become wrapped around one another. And in observing you become part of the ongoing equation. Look away now. Next up, in the third lesson, ‘The Architecture of the Cosmos’.