How Do You Pronounce Ψ?

Let our journalists help you make sense of the noise: Subscribe to the Mother Jones Daily newsletter and get a recap of news that matters.

Chad Orzel linked yesterday to a post by Sabine Hossenfelder about quantum superposition, and it unsurprisingly degenerated into the usual mush that interpretations of quantum mechanics always do. But then the subject turned to linguistics and it got interesting. As you may know, the quantum wave function is represented by the Greek letter psi (Ψ), with |Ψ²| representing the probability of a particle being found in any particular place.¹ So a reader decided to try on a joke in comments:

How should Psi be pronounced? Is it P-Si, Si, or a superposition of the two? Or is the word not pronounceable until it is spoken, like when Prince changed his name.

But Hossenfelder took the question seriously:

Well, I pronounce it the way that I have heard it most often which in English is “ps-ai” (in German it would be “ps-ee”). The easiest way to find out I guess is to listen to the video? I have no idea which one is the “correct” pronunciation, given that it’s Greek and I don’t speak Greek, but I can tell you that if you pronounce it this way physicists will know what you are talking about.

Huh. I’ve always pronounced it sigh, rhymes with pie. It never occured to me that you’d pronounce the initial P.² So I googled around a bit and got conflicting answers, which I suppose is very on-brand. However, on one particular site the speaker was clearly pronouncing it p-sigh, but with just the barest emphasis on the P. The best I can describe it is that it sounded as if the P was trailing off before it even got started, followed by a normal pronunciation of sigh.

So I guess this is a question for physicists, or anyone who’s taken a quantum physics course. Is Ψ usually pronounced with its initial P? If so, how distinct is it?

¹More or less. Don’t @ me with your eigenvalues and inner products.

²And you don’t pronounce the initial P if you’re using psi as short for psionic. We are talking here solely about the pronunciation of Ψ in its quantum mechanical sense.

UPDATE: Answer here!

THE TRUTH IS...

what drives Mother Jones' team of 50-plus journalists. The truth is powerful, as evidenced by how hard those with something to hide, or profit to gain, seek to discredit it. The truth, stated boldly and reported meticulously, is what draws so many readers to Mother Jones.

And the truth is, going into the final 4 days of the year we still needed to raise $TK to hit our $350,000 goal and start 2021 on track. It's nerve-wracking, wondering if the big spike we normally see at the end of December is going to be another thing that doesn't go as planned in 2020, or worse, if, now that Donald Trump is set to leave the White House (for longer than a taxpayer-funded golf trip to a property he owns), folks might be pulling back from fighting for the truth and a democracy and think the hard work is done.

It's not, and if you can right now, please consider a year-end donation to support our team's fearless nonprofit journalism so we can close that big fundraising gap and finish the year strong, ready for all that's ahead in 2021. Whether you can give $5 or $500, it all matters in keeping us charging hard, and we'd be grateful.

payment methods

THE TRUTH IS...

what drives Mother Jones' team of 50-plus journalists. The truth is powerful, as evidenced by how hard those with something to hide, or profit to gain, seek to discredit it. The truth, stated boldly and reported meticulously, is what draws so many readers to Mother Jones.

And the truth is, going into the final 4 days of the year we still needed to raise $TK to hit our $350,000 goal and start 2021 on track. It's nerve-wracking, wondering if the big spike we normally see at the end of December is going to be another thing that doesn't go as planned in 2020, or worse, if, now that Donald Trump is set to leave the White House (for longer than a taxpayer-funded golf trip to a property he owns), folks might be pulling back from fighting for the truth and a democracy and think the hard work is done.

It's not, and if you can right now, please consider a year-end donation to support our team's fearless nonprofit journalism so we can close that big fundraising gap and finish the year strong, ready for all that's ahead in 2021. Whether you can give $5 or $500, it all matters in keeping us charging hard, and we'd be grateful.

payment methods

We Recommend

Latest

Sign up for our free newsletter

Subscribe to the Mother Jones Daily to have our top stories delivered directly to your inbox.

Get our award-winning magazine

Save big on a full year of investigations, ideas, and insights.

Subscribe

Support our journalism

Help Mother Jones' reporters dig deep with a tax-deductible donation.

Donate