Millisecond spin lifetimes in quantum dots at zero applied magnetic   field due to strong electron-nuclear interaction
  A key to achieving ultra-long electron spin memory in quantum dots (QDs) at 0~$T$ is the polarization of the nuclei, such that the electron spin is stabilized along the nuclear magnetic field. We demonstrate that spin-polarized electrons in n-doped QDs align the nuclear field via the hyperfine interaction. A feedback onto the electrons occurs, leading to stabilization of electron polarization. We suggest that the coupled electron-nuclear system forms a rigid nuclear spin polaron state as predicted by I.A.~Merkulov, for which spin memory is retained over millisecond lifetimes. 
A. Greilich, R. Oulton, S. Yu. Verbin, R.V. Cherbunin, T. Auer, D.R.   Yakovlev, M. Bayer, V. Stavarache, D. Reuter, and A. ...