A post about bras and LOLKets

First, go read this webcomic, which made me laugh a lot. I wrote to the author, figuring I was the 800th person to write in and suggest that he could have titled the strip LOL-Kets. Evidently I’m the first person to think of that, so go figure!

Which leads me to this wikipedia article on bra-ket notation. You see, Paul Dirac came up with bras and kets back in the 1920s as a shorthand way of writing down a wavefunction (for example) and its conjugate transposition. Like so:

< B |     this is a “bra”

| B >     this is a “ket”

Together they make < B | B >, a “bra-ket”, which Dirac invented by slicing the word “bracket” into two parts. I bring all this up for three reasons:

1. Plenty of grad students made jokes about the “bra” part of bra-ket notation, for obvious reasons, but this is the first time I found an excuse to make a “ket” joke. Naturally, I’m delighted.
2. It gives me a chance to complain that there is no “bra-kets in popular culture” section of the Wiki article, and…
3. I just want to point out that #2 is partially explained by the fact that Paul Dirac was a startlingly humorless character (see Paul Dirac — Personality for fun facts!), who assuredly had no interest in fomenting nomenclatural mirth.

So, boooo to humorless physicists, and yaaaaay to Abstruse Goose! You should go read them all, especially if you wish xkcd was even geekier.