1212.3655 (Shengjun Wu)

State tomography via weak measurements    [PDF]

Shengjun Wu

It was realized recently that the wave function of a pure state can be measured directly, and complementary knowledge of a quantum system can be obtained simultaneously by weak measurement. However, the scheme applies only to pure states, and it is not efficient as most data are thrown away by post-selection. Here we propose tomography schemes for pure states as well as for mixed states via weak measurements, and our schemes are more efficient as we don't throw away any data. Furthermore, we shall show that any matrix element of a general state can be directly read out from an appropriate weak measurement. The density matrix (with all its elements) represents all that is directly accessible from a general measurement.

View original: http://arxiv.org/abs/1212.3655