@article {1345, title = {Self-Consistent Measurement and State Tomography of an Exchange-Only Spin Qubit}, journal = {Nature Nanotechnology}, volume = {8}, year = {2013}, month = {2013/9/1}, pages = {654 - 659}, abstract = {We report initialization, complete electrical control, and single-shot readout of an exchange-only spin qubit. Full control via the exchange interaction is fast, yielding a demonstrated 75 qubit rotations in under 2 ns. Measurement and state tomography are performed using a maximum-likelihood estimator method, allowing decoherence, leakage out of the qubit state space, and measurement fidelity to be quantified. The methods developed here are generally applicable to systems with state leakage, noisy measurements, and non-orthogonal control axes. }, doi = {10.1038/nnano.2013.168}, url = {http://arxiv.org/abs/1302.1933v1}, author = {J. Medford and J. Beil and J. M. Taylor and S. D. Bartlett and A. C. Doherty and E. I. Rashba and D. P. DiVincenzo and H. Lu and A. C. Gossard and C. M. Marcus} }