Electron Spin Excited States Spectroscopy in a Quantum Dot Probed by QPC   Back-action
  The quantum point contact (QPC) back-action has been found to cause non-thermal-equilibrium excitations to the electron spin states in a quantum dot (QD). Here we use back-action as an excitation source to probe the spin excited states spectroscopy for both the odd and even electron numbers under a varying parallel magnetic field. For a single electron, we observed the Zeeman splitting. For two electrons, we observed the splitting of the spin triplet states $|T^{+}>$ and $|T^{0}>$ and found that back-action drives the singlet state $|S>$ overwhelmingly to $|T^{+}>$ other than $|T^{0}>$. All these information were revealed through the real-time charge counting statistics. 
HaiOu Li, Ming Xiao, Gang Cao, Cheng Zhou, RuNan Shang, Tao Tu,   GuangCan Guo, HongWen Jiang, and GuoPing Guo
cond-mat.mes-hall