Tutorial: Quantum Theory of Measurement

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Prof. Choi, Mahn-Soo (Korea University)


Unlike in classical mechanics, measurement is highly non-trivial in quantum mechanics as one can see from the hypothesis of wave function collapse. Even more serious is the fundamental limit due to the uncertainty principle, which cannot be beat by however advanced technical instruments. In this tutorial, we introduce the basic principle and formulation of measurement in quantum mechanics, and discuss several quantum-enhanced methods for precision measurement to overcome the so-called standard quantum limit (SQL) while not violating the uncertainty principle. Examples are taken from solid-state qubit systems to illustrate the ideas of quantum non-demolition measurement (QND), the entanglement-enhanced precision measurement, the weak measurement, and so on.