Scientists have made a satisfying and intriguing physics discovery some 16 years after it was first predicted to be a possibility: a quasiparticle (a group of particles behaving as one) that only has an effective mass when moving in one direction.

tl;dr by ChatGPT:

Scientists have discovered a quasiparticle, the semi-Dirac fermion, which behaves unusually by having mass in one direction but being massless in another. Found in a ZrSiS crystal at extremely low temperatures, this particle challenges conventional physics. Researchers used magneto-optical spectroscopy and strong magnetic fields to observe it. The discovery opens new possibilities in quantum physics and electronics, though many questions remain unanswered.

Deutsch:

Wissenschaftler haben ein Quasiteilchen, das semi-Dirac-Fermion, entdeckt, das in eine Richtung masselos ist, in die andere jedoch Masse hat. Es wurde in einem ZrSiS-Kristall bei extrem niedrigen Temperaturen gefunden. Mithilfe von Magneto-Optischer Spektroskopie und starken Magnetfeldern konnte dieses ungewöhnliche Verhalten beobachtet werden. Die Entdeckung eröffnet neue Möglichkeiten in der Quantenphysik, wirft aber noch viele Fragen auf.

Paper: Semi-Dirac Fermions in a Topological Metal | PDF

    • peto (he/him)@lemm.eeEnglish
      5·
      3 days ago

      Unfortunately I think the directions are only local to the crystal lattice. And being a quasiparticle it is confined to the crystal.

      On the up side, you could probably consider this to be an actual magic crystal with special properties, so there is that.

    • Mastema@infosec.pub
      6·
      3 days ago

      Regrettably, most of my mass is in a direction I would have to call, “down”…

      (I don’t understand it either, so I’ll be self-deprecating!)

      • 𝕽𝖚𝖆𝖎𝖉𝖍𝖗𝖎𝖌𝖍@midwest.social
        2·
        2 days ago

        I was thinking about resistance, and energy required to lift things. But that works, too. I think “backwards” is also a good choice.

        I’m studiously ignoring the reply that informed me that the direction is local, not universal, because that’s boring.

  • henfredemars@infosec.pubEnglish
    2·
    3 days ago

    Interesting, but I do think it’s important to note for the layperson that these aren’t real particles, no? They are groups that appear to change their emergent group property. That’s not the same as saying a particle is actually massless in one direction through a crystal lattice.