Minimal time trajectories for two-level quantum systems with two bounded controls
http://scitation.aip.org/content/aip/journal/jmp/55/6/10.1063/1.4882158
http://arxiv.org/abs/1211.0666
http://scitation.aip.org/content/aip/journal/jmp/55/6/10.1063/1.4882158
http://arxiv.org/abs/1211.0666