If the theorists are right, the quasiparticle excitations of the 5/2 quantum Hall state share a remarkable collective degeneracy that can be exploited for fault-tolerant quantum computing (see Physics Today, October 2005, page 21). But before experimenters can build even a single logic gate, they need to confirm the 5/2 state’s true nature. And before they do that, they need to trap the 5/2 state within the confines of a gated quantum dot or quantum point contact. That preliminary step has just been carried out. Jeff Miller of Harvard University and his collaborators from Alcatel-Lucent’s Bell Labs, Harvard, and MIT fabricated seven different-sized QPCs out of a semiconductor heterostructure made from gallium arsenide and aluminum gallium arsenide (see figure). Using clever tunings of voltages and magnetic fields, Miller and his collaborators observed the 5/2 state not only in the gallium arsenide bulk of the heterostructure but also...

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