Control of quantum bits in silicon paves way for large quantum computers
Lead researcher, UNSW Associate Professor Andrea Morello from the School of Electrical Engineering and Telecommunications, said his team had successfully realised a new control method for future quantum computers. The team has already improved the control of these qubits to an accuracy of above 99% and established the world record for how long quantum information can be stored in the solid state, as published in Nature Nanotechnology in 2014. We demonstrated that a highly coherent qubit, like the spin of a single phosphorus atom in isotopically enriched silicon, can be controlled using electric fields, instead of using pulses of oscillating magnetic fields, explained UNSW’s Dr Arne Laucht, post-doctoral researcher and lead author of the study. Associate Professor Morello said the method works by distorting the shape of the electron cloud attached to the atom, using a very localized electric field. Key to the success of this electrical control method is the placement of the qubits inside a thin layer of specially purified silicon, containing only the silicon-28 isotope.