Cotunneling Spectroscopy in Few-Electron Quantum Dots
  Few-electron quantum dots are investigated in the regime of strong tunneling to the leads. Inelastic cotunneling is used to measure the two-electron singlet-triplet splitting above and below a magnetic field driven singlet-triplet transition. Evidence for a non-equilibrium two-electron singlet-triplet Kondo effect is presented. Cotunneling allows orbital correlations and parameters characterizing entanglement of the two-electron singlet ground state to be extracted from dc transport. 
D. M. Zumbuhl, C. M. Marcus, M. P. Hanson, A. C. Gossard