It's Not a Proper Cat

Last week there was a splash in the news about a new particle that had been discovered, called a Majorana particle. Sadly, the coverage was disappointing, but since I had spent most of the week standing on my porch and shaking my fist at things, (and it’s not really my area of physics) I didn’t blog about it.

In short, this new discovery was a quasi-particle, i.e. a composite system, which was information that was buried in every article I read. To me this is reminiscent of the magnetic monopole coverage from a while back, which was another quasi-particle. Interesting, to be sure, but not really what was advertised in the headline.

Turns out, I wasn’t the only one a little miffed at how it was reported. Jon Butterworth was, too.
Majorana particles – Fundamentally confusing

… I was excited to read about the new particle, and somewhat diappointed when I did so to find out that it is not a fundamental Majorana fermion, still less a neutrino. A bit of a let-down for me and my particle-physics colleagues. Nevertheless, the result is interesting for a number reasons.

What has been seen is a quantum state in one-atom-thick wire which in a certain energy range behaves like a Majorana fermion. It is not a fundamental particle, it is a composite state, and the behaviour emerges from the interactions of atoms, electrons and photons, described by quantum electrodynamics, in which all fermions are Dirac. The fact that Majorana behaviour has been predicted, and then observed, to emerge as collective behaviour from a “more fundamental” (i.e. higher energy, shorter distance scale) theory is fascinating.

Neat stuff, no need to sex it up with the misleading inference that it’s an actual particle. And a good explanation of what’s what to boot.

Obscure title reference

2 thoughts on “It's Not a Proper Cat

  1. This reminds me of some of the fuss about splitting electrons. Really the properties were shared among three quasi-particles the so called holons, spinons and orbitons. Like this Majorana quasi-particle this is amazing; you get some rather strange and wonderful emergent collective behaviour.

    Is there some ‘physics sexiness’ here? I mean, it has to be something to do with fundamental particles, high energy physics and CERN or we are not interested, right?

  2. Yes, that’s another good example. I think in all of these cases the physics can stand on its own without being hyped as being something it’s not.

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