Effect of Quantum Point Contact Measurement on Electron Spin State in   Quantum Dot
  We study the time evolution of two electron spin states in a double quantum-dot system, which includes a nearby quantum point contact (QPC) as a measurement device. We obtain that the QPC measurement induced decoherence is in time scales of microsecond. We also find that the enhanced QPC measurement will trap the system in its initial spin states, which is consistent with quantum Zeno effect. 
Fei-Yun Zhu, Zhi-Cheng Zhu, Tao Tu, Hua Tu, Guang-Can Guo, Guo-Ping   Guo