A Formula for Love

It’s St. Valentine’s Day! Quite possibly the most annoying day of the year, what with all those loving lovers looking for love gushing about it.

Some, we’re sad to say, are finding attraction in a very strange place. In what some physicists describe as one of the most elegant and beautiful equations ever written.

(i∂̸ – m) ψ = 0

If you’re up on your physics, you’ll immediately recognize this formula as the work of Paul Dirac. It combines Einstein’s theory of relativity with quantum theory to describe how microscopic particles like electrons act when they travel at speeds near the speed of light. It’s that connection with quantum theory is apparently all that’s needed to hook the lovelorn on Dirac’s math as an expression of love.

If you have seen this equation tattooed on someone’s body, it’s because it not only describes the phenomenon of quantum entanglement, but has also been called the formula for love. Why? Because the equation implies that if two particles are connected for a time and then separate, what happens to one will continue to affect the other despite the separation.

Popular culture has somehow taken a mathematical equation to be the formula for love. It’s a strange turn of events for the ascetic physicist, part genius and part madman, who devised such a beautiful equation. It has now transcended the scientific world and has become a tattoo on young people who seal their love with padlocks on bridge railings.

Here’s a screenshot of the infamous tattooed expression of love as shared on social media:

What could possibly go wrong with such a metaphorical expression of love in a formula involving quantum entanglement?

If you ask quantum physicists, plenty. Mainly because they know the equation doesn’t say anything like what the people tattooing it on themselves seem to think it says.

Thomas Pashby, an assistant professor in the Department of Philosophy at the University of Chicago, whose research concerns the interpretation of quantum mechanics, told AAP FactCheck the Dirac equation described a single electron: “It is notable for providing an elementary description of the electron in a hydrogen atom which gets the energy levels almost exactly right (apart from some small corrections from quantum field theory).”

Asst Prof Pashby confirmed the photo of the tattoo in the post was the Dirac equation, but that the equation was incorrectly written in the post itself ((∂ + m) ps = 0), since it was missing the “Feynman slash notation”.

He said the interpretative part of the text was “essentially nonsense” and entanglement was not a phenomenon the Dirac equation describes “since it applies to a single electron”.

Whoops! Don’t you hate it when your permanently applied ink doesn’t really say what you thought it did?

Here’s the bottom line. While it may indeed be among the most elegant of equations, the Dirac equation is a formula that only a physicist who understands it can truly love.