The long-sought Majorana fermion, first postulated to exist in the 1930s, may have at last been isolated in the laboratory. Nanoscientists at TU Delft’s Kavli Institute and the Foundation for Fundamental Research on Matter in the Netherlands, otherwise known as the FOM foundation, succeeded in detecting very compelling evidence for the particle in experiments performed over the past few months. The team, led by physicist Leo Kouwenhoven, published their findings online on April 12, 2012 in Science.
The existence of this elusive fermion, which is identical to its own antiparticle, was first theorized by Italian physicist Ettore Majorana through his analysis of the wave equations of quantum mechanics. The FOM Foundation’s research, which was sponsored in part by Microsoft, focused on exploiting certain properties of semiconductors to locate the particle. If confirmed, this discovery would have great implications both for cosmology (dark matter may be made of Majorana particles), and for the development of the quantum computer, that holy grail of the information age.
One thing that makes quantum computers so alluring is their potential to perform so many calculations at once. A traditional silicon-based computer stores information in memory in terms of bits, where each bit is either a one or a zero. A quantum computer, however, uses qubits, which each one representing a one, a zero, or a quantum superposition of the two—which in simple terms means that the information can exist in several states simultaneously. In practice, this can allow quantum computers to perform some tasks many orders of magnitudes faster than traditional computers, making them potentially very valuable for certain applications.
Thus far, a major challenge in the development of practical versions of these machines has been in preserving the information in these quantum qubits long enough to make any use of it. Majorana particles, however, are believed to have properties allowing them to essentially “remember” their former positions when they move around, which would make them uniquely suited for storing information at the qubit level. This novel property, says Robert Service of Science, is “something that has eluded researchers for decades.”
- V. Mourik, K. Zuo, S. M. Frolov, S. R. Plissard, E. P. A. M. Bakkers, L. P. Kouwenhoven. Signatures of Majorana Fermions in Hybrid Superconductor-Semiconductor Nanowire Devices. Science, 2012. DOI: 10.1126/science.1222360
- R.F. Service. Search for Majorana Fermions Nearing Success at Last? Science 8 April 2011: 332 (6026), 193-195. DOI: 10.1126/science.332.6026.193