Physics World October 10, 2019
A team of researchers in the US (University of Rochester, Purdue University) has demonstrated coherent spin-state transfer along an array of four electrons confined in a quadruple quantum dot in a GaAs/AlGaAs heterostructure. When they applied a voltage pulse to a gate between two quantum dots, the electrons in the dots exchanged their spin states via Heisenberg exchange coupling. By applying a series of voltage pulses to specific gates, the researchers were able to shuttle the spin states of the electrons back and forth. They were able to transmit the spins of entangled electrons using the same technique. In the next steps they plan to go to greater lengths and incorporate more electrons in the same GaAs/AlGaAs system. As there is no theoretical limit on how far spin transmission can reach, Heisenberg exchange will be useful for multi-qubit gates and error correction in spin-based quantum computers…read more. Open Access TECHNICAL ARTICLE
Electron spin state transfer via swapping in a linear spin qubit array. Credit: John Nichol