Welcome to another episode of Sciency Words, a special series here on Planet Pailly where we take a closer look at the definitions and etymologies of science or science-related terms so we can expand our scientific vocabularies together. Today’s term is:
I’m starting to think I can get used to just about any weird quirk of language. When I first saw the word qubit, referring to the quantum bits inside a quantum computer, I’m pretty sure my eye twitched. The spelling of that word… it just looks so… so wrong.
And I’m not the only one who to feel that way. In a paper titled “From Cbits to Qbits,” American physicist N. David Mermin laments that “the prevailing ‘qubit’ honors the English rule that q should be followed by u but ignores the equally powerful requirement that qu should be followed by a vowel.” Mermin would prefer the spelling qbit. I would prefer the hyphenated form q-bit. Unfortunately, neither of those options seem to have caught on.
So who is responsible for this crime against English spelling rules? It was another American physicist by the name of Benjamin Schumacher, who originally introduced the term in this 1995 paper on quantum information theory. In the brief acknowledgements section at the end of the paper, Schumacher explains: “The term ‘qubit’ was coined in jest during one of the author’s many intriguing and valuable conversations with W.K. Wootters, and became the initial impetus for this work.”
As a writer, I kind of identify with Schumacher here. I’ve had the experience many times of either learning a new word or inventing one, and having that spur fresh and exciting new thoughts. But still, why is the word spelled that way?
Several other sources (including Wiktionary) say the word qubit is formed by analogy with cubit, the ancient unit of measure equal to the length of an adult male’s forearm (from elbow to fingertips). There is a certain inherent uncertainty involved in cubit-based measurements, given the amount of variation there can be among adult male forearms. So I guess connecting that to all the inherent uncertainties of quantum science and quantum computing makes a sort of sense.
I don’t know. Maybe I’ve gotten so used to seeing the word spelled the way it’s spelled that it doesn’t bug me as much as it used to. And knowing a little about the word’s history, and its apparent association with the cubit, probably helps to make the weird spelling a little more palatable for me. But what about you? Are you okay with qubit, or does that weird spelling make your eye twitch when you see it?