What Are Majorana Particles and What Are their Potential Uses?

[Bobbywhy]

Published in “Science Online” 12 April 2012:

“Signatures of Majorana Fermions in Hybrid Superconductor-Semiconductor Nanowire Devices”
by V. Mourik, K. Zuo, S. M. Frolov, S. R. Plissard, E. P. A. M. Bakkers, and L. P. Kouwenhoven

Abstract
Majorana fermions are particles identical to their own antiparticles. They have been theoretically predicted to exist in topological superconductors. We report electrical measurements on InSb nanowires contacted with one normal (Au) and one superconducting electrode (NbTiN). Gate voltages vary electron density and define a tunnel barrier between normal and superconducting contacts. In the presence of magnetic fields of order 100 mT, we observe bound, mid-gap states at zero bias voltage. These bound states remain fixed to zero bias even when magnetic fields and gate voltages are changed over considerable ranges. Our observations support the hypothesis of Majorana fermions in nanowires coupled to superconductors.
http://www.sciencemag.org/content/early/2012/04/11/science.1222360


(Nanowerk News) Scientists at TU Delft's Kavli Institute and the Foundation for Fundamental Research on Matter (FOM Foundation) have succeeded for the first time in detecting a Majorana particle. In the 1930s, the brilliant Italian physicist Ettore Majorana deduced from quantum theory the possibility of the existence of a very special particle, a particle that is its own anti-particle: the Majorana fermion.

That 'Majorana' would be right on the border between matter and anti-matter.
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. Such a computer is far more powerful than the best supercomputer, but only exists in theory so far. Contrary to an 'ordinary' quantum computer, a quantum computer based on Majorana fermions is exceptionally stable and barely sensitive to external influences.
http://www.nanowerk.com/news/newsid=24904.php

 

[Bill_K]

This is a very interesting discovery, but one should remember that the states under discussion are quasiparticles in a superconductor, not fundamental particles, and have nothing to do with dark matter or cosmology.