Subject：Further investigation on quantum measurement using a trapped ion system
Speaker：Prof. Pingxing Chen
Emcee：Prof. Guangjiong Dong
Time：10:00am, 15th Oct, 2020
Place：Optics building A508
Abstract：
Quantum measurement has been an important and vague topic in quantum mechanics. Two complementary measurement schemes have been widely investigated in a variety of quantum systems, i.e. von Neumann's projective (strong) measurement (1932) and Aharonov's weak measurement (1988). Recent some experiments showed the weak measurement with photons. Here, we present the first proof-of-principle experimental demonstration of purely atomic WVA using a single trapped 40Ca+ ion. And then we report the observation of measurement transition from weak to strong in a single trapped 40+ 27 ion system. The transition is realized by tuning the interaction strength between the ion's internal electronic state and its vibrational motion, which play the roles of the measured system and the measuring apparatus, respectively. More precisely, the weak-to-strong measurement transition is characterized by a universal transition factor. This transition, which continuously connects weak measurement and strong measurement, is capable of opening new experimental possibilities for testing quantum foundations. It also prompts us to reexamine and improve the measurement schemes of related quantum technologies.
