Weak measurements as an instance of non-ideal measurements
We introduce weak measurements (WM) as a type of non-ideal measurement (NIM) coupling the system and the measuring device in a specific manner involving a weak interaction followed by post-selection. For the particular case of a WM measurement of spin, we solve the quantum dynamics for the coupled system-meter ensemble exactly for any type of non-ideal measurement. The standard WM regime is obtained as a limiting case; eccentric “semi-weak” values not only appear in other cases of NIM, but can also have a larger magnitude than the usual weak values. A couple of examples comparing the merits of the WM regime and of the exact treatment in situations of potential interest to quantum information applications are considered.
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- 12.Y. Shikano, in Measurements in Quantum Mechanics, Ed. by M. R. Pahlavani (InTech, 2012), Ch. 4.Google Scholar
- 24.P. E. Toschek and C. Balzer, Laser Phys. 12, 253 (2002).Google Scholar
- 27.D. N. Klyshko, Laser Phys. 8, 363 (1998).Google Scholar
- 28.A. Bassi and G. Ghirardi, 379, 257 (2003).Google Scholar