Wednesday, March 6, 2013

1303.1034 (Floris R. Braakman et al.)

Long-range coherent coupling in a quantum dot array    [PDF]

Floris R. Braakman, Pierre Barthelemy, Christian Reichl, Werner Wegscheider, Lieven M. K. Vandersypen
Controlling long-range quantum correlations is central to quantum computation and simulation. In quantum dot arrays, experiments so far rely on nearest-neighbour couplings only, and inducing long-range correlations requires sequential local operations. Here we show that two distant sites can be tunnel coupled directly. The coupling is mediated by virtual occupation of an intermediate site, with a strength that is controlled via the energy detuning of this site. It permits a single charge to oscillate coherently between the outer sites of a triple dot array without passing through the middle, as demonstrated through the observation of Landau-Zener-St\"uckelberg interference. The long-range coupling significantly improves the prospects of fault-tolerant quantum computation using quantum dot arrays and opens up new avenues for performing quantum simulations in nanoscale devices.
View original: http://arxiv.org/abs/1303.1034

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