Electron spin coherence in semiconductors: Considerations for a spin-based solid state quantum computer architecture

摘要

We theoretically consider coherence times for spins in two quantum computerarchitectures, where the qubit is the spin of an electron bound to a P donorimpurity in Si or within a GaAs quantum dot. We show that low temperaturedecoherence is dominated by spin-spin interactions, through spectral diffusionand dipolar flip-flop mechanisms. These contributions lead to 1-100 $\mu$scalculated spin coherence times for a wide range of parameters, much higherthan former estimates based on $T_{2}^{*}$ measurements.