Slashdot Mirror
Scientists Find Long-Sought Majorana Particle
New submitter boner writes "In a follow-up to an earlier Slashdot story, scientists at the Technical University of Delft in the Netherlands yesterday published their findings that they have indeed found the Majorana particle. The announcement on the university website provides both a summary of the academic paper (PDF) and background of this groundbreaking discovery. Quoting: 'Majorana fermions are very interesting – not only because their discovery opens up a new and uncharted chapter of fundamental physics; they may also play a role in cosmology. A proposed theory assumes that the mysterious ‘dark matter, which forms the greatest part of the universe, is composed of Majorana fermions. Furthermore, scientists view the particles as fundamental building blocks for the quantum computer.'"
Did I read the article correctly that this was funded by Microsoft? That's sort of coolish...
When two of them meet, they annihilate. Note from the article that there are two of these things, and they are at opposite ends of the nanowire. Presumably when you turn off the power or cooling they get together and turn back into energy.
Dark matter is suspected to be the same - when two particles meet, they annihilate, potentially giving us a signal we can measure. They don't meet very often though, because dark matter barely interacts with anything, including itself.
Not a technical explanation, but a good one I heard: if you look at a Feynman diagram (they're pretty easy to understand for a layman) you'll find that you can read them in any direction - if you go "against the time arrows" you're just looking at the antiparticle versions interacting instead, it's still a valid diagram. However, the photons don't have arrows as they don't experience time, so they're identical in either time direction, and therefore their own antiparticles.
The interesting thing here is that it's a massive particle with that property, rather than a massless one.
Please consider this account deleted, I just can't be bothered with the spam anymore.
All elementary particles have an antiparticle of opposite charge
get published. That would be "all" except for the photon, gluon and Z which are their own anti-particle and possibly the neutrino which might actually be a majorana fermion (we just don't know yet - underground experiments are looking into this). The webpage article is no better because it gets hopelessly confused about the difference between a fundamental particle and a condensed matter excitation. However at least that did not have to pass a referee - the journal Science should be ashamed!