Long-lived memory for electronic spin in a quantum dot: Numerical   analysis
  Techniques for coherent control of electron spin-nuclear spin interactions in quantum dots can be directly applied in spintronics and in quantum information processing. In this work we study numerically the interaction of electron and nuclear spins in the context of storing the spin-state of an electron in a collective state of nuclear spins. We take into account the errors inherent in a realistic system: the incomplete polarization of the bath of nuclear spins and the different hyperfine interactions between the electron and individual nuclei in the quantum dot. Although these imperfections deteriorate the fidelity of the quantum information retrieval, we find reasonable fidelities are achievable for modest bath polarizations. 
V. V. Dobrovitski, J. M. Taylor, M. D. Lukin