Abstract: Measurement and estimation of parameters are essential for science and engineering, where the main quest is to find out the highest achievable precision with given resources and design schemes to attain it. With recent development of technology, it is now possible to design measurement protocols utilizing quantum mechanical effects, such as entanglement, to attain far better precision than classical schemes. This has found wide applications in quantum phase estimation, quantum imaging, atomic clock synchronization, etc, and created a high demand for better understanding of measurement protocols based on quantum mechanical effects. In this talk I will present a general framework for quantum mechanical metrology which relates the ultimate precision limit to the underlying quantum dynamics. This framework provides efficient methods for computing the ultimate precision limit and optimal schemes to attain it. It also provides an analytical formula of the precision limit with arbitrary pure probe states, which spares the need of optimization required in previous studies. It is also shown that with noiseless dynamics a universal time scaling emerges as a fundamental property under the optimal scheme for quantum parameter estimation, this restores an intuition that has been recently questioned in the field, that time is always a valuable resource.
Biography: Haidong Yuan received the Bachelor’s degree from Tsinghua University and PhD from Harvard University. He then did his postdoctoral work at Massachusetts Institute of Technology. From 2012 to 2014 he was an assistant professor at the department of Applied Mathematics, the Hong Kong Polytechnic University. Currently he is an assistant professor at the department of Mechanical and Automation Engineering, the Chinese University of Hong Kong.