Occasional reflections on Life, the World, and Mathematics

Quantum babble


Here’s  a recent article from New Scientist about the discovery — creation, actually — of a new kind of particle called the “Majorana fermion” that physicists have supposedly been searching for for 75 years (who knew?!)

I more or less trust New Scientist, so it’s presumably legitimate, but it’s amazingly close to a parody of quantum gobbledegook. I know more than the average person about quantum physics, but I really can’t tell if someone’s pulling my leg here. I could just as well imagine this having been scribed by Stanislaw Lem, and it wouldn’t be entirely out of place as a wonky Spock-Kirk colloquy in Star Trek, explaining how hyperwarp communications or something functions.

What is a Majorana fermion?

It is named for the physicist Ettore Majorana, who found that a particle could be its own antiparticle.

If a particle has properties with values unequal to zero, then its antiparticle has the opposite values. What that means is that all the properties of a Majorana fermion, the charge, energy, what have you, it’s all zero. It is a particle, but it doesn’t have properties that we can measure. That makes it very mysterious. It also makes it difficult to find.

How did you find the Majorana?
We made one. The Majorana comes out of the superposition of an electron and a “hole” – the absence of an electron in a metal. By applying a magnetic field to semiconducting nanowires laid across a superconductor, you can move electrons along these wires, creating two points in space that each mimic half an electron. The electrons go back and forth, so the hole jumps from left to right. If it spends an equal amount of time on each side, then, quantum mechanically, it’s in a superposition of being on the left and right. If it’s stable, then we call it a particle.

I’ve had graduate level courses in relativistic quantum mechanics, but I can’t tell if this is a joke.

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