Physics

Weaving a Quantum Computer

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Science  16 Jan 2009:
Vol. 323, Issue 5912, pp. 311
DOI: 10.1126/science.323.5912.311d

Quantum matter can be described by a quantum-mechanical wave function. Correlated phases of such matter can give rise to excitations that have been proposed to be useful for quantum computation. Of particular interest are those excitations that exhibit Abelian or non-Abelian statistics. Anyons fall into this category and are particle-like excitations. Compared with bosons or fermions, where swapping two will respectively keep the wave function as it is or introduce a negative sign, swapping two anyons is quite different—the action imposes a nontrivial phase shift on the wave function so that when a number of anyon swaps have been performed, measurement of the phase can tell you exactly which particles have been swapped. Such a braiding technique is at the heart of some quantum computation schemes, but exactly how these states would be manipulated experimentally is still up for grabs. Aguado et al. propose that a lattice of atoms held in an optical trap could be one such realization, showing how the manipulation of atoms in their respective lattice sites can affect the wave function describing the whole ensemble, which can be read out quantitatively. — ISO

Phys. Rev. Lett. 101, 260501 (2008).

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