Kane quantum computer

Firstly, the state has an extremely long decoherence time, perhaps on the order of 1018 seconds at millikelvin temperatures.

Secondly, the qubits may be manipulated by applying an oscillating magnetic field, as in typical NMR proposals.

Then, a potential is applied to the J gate, drawing adjacent donor electrons into a common region, greatly enhancing the interaction between the neighbouring spins.

Secondly and perhaps more importantly, it's not clear that the D– state has a sufficiently long lifetime to allow for readout—the electron tunnels into the conduction band.

Experimentally, atomic-precision deposition of phosphorus atoms has been achieved using a scanning tunneling microscope (STM) technique in 2003.

[3] Detection of the movement of single electrons between small, dense clusters of phosphorus donors has also been achieved.