Semi-classical model for the dephasing of a two-electron spin qubit   coupled to a coherently evolving nuclear spin bath
  We study electron spin decoherence in a two-electron double quantum dot due to the hyperfine interaction, under spin-echo conditions as studied in recent experiments. We develop a semi-classical model for the interaction between the electron and nuclear spins, in which the time-dependent Overhauser fields induced by the nuclear spins are treated as classical vector variables. Comparison of the model with experimentally-obtained echo signals allows us to quantify the contributions of various processes such as coherent Larmor precession and spin diffusion to the nuclear spin evolution. 
Izhar Neder, Mark S. Rudner, Hendrik Bluhm, Sandra Foletti, Bertrand   I. Halperin and Amir Yacoby
cond-mat.mes-hall