Weak measurement with a single qubit
Michael Steiner · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 2004
Weak measurement is a technique whereby the coupling between the measuring device and the observable is sufficiently weak that the uncertainty in a single measurement is large compared with the separation between the eigenvalues of the observable. It is found here that weak measurement can be achieved with a single qubit. An additional feature of using single qubits as weak measurement devices is that the entanglement that results between the measured and measuring qubits can be easily quantified. An analysis is provided of the effect of entanglement using an example similar to the Hardy paradox of double interferometers with positron-electron annihilation.