A benchmark of a precision metrology scheme is its precision when using a fixed amount of resources, for example, the total energy or number of particles involved in the measurement process. Quantum metrology as an emerging technology provides a more efficient method to utilize the resource in precision measurement compared to the classical means. Yet the delicate nature of quantum states makes them very sensitive to experimental imperfections such as loss and decoherence. Therefore to achieve the quantum-enhanced precision in practice requires both the careful design of novel quantum metrology schemes as well as the development of quantum sources and detectors. In the first part of the talk I will introduce a quantum metrology scheme that is both robust against experimental imperfections and feasible with current technologies.

In the second part of the talk I will discuss the precision metrology using weak measurements. Weak measurement may lead to highly counter-intuitive phenomena, such as the possibility to dramatically amplify a small effect. It has received increasing interest due to its potential application in metrology. Yet the amplification effect of weak measurement comes at the cost of a reduction in the rate at which data can be acquired. Therefore whether weak measurement can really enhance the measurement precision or even beat the classical limit is still unclear. Utilizing the tools developed in quantum metrology, we benchmark the precision of weak measurement and provide answers to three vital questions in weak-measurement-based metrology.
 
个人简介: Lijian received his PhD at the department of physics, University of Oxford. He stayed in Oxford as a postdoc researcher, then moved to the Max Planck Institute for the Structure and Dynamics of Matter in Hamburg as a Humboldt research fellow. In 2013 he joined the faculty of College of Engineering and Applied Sciences at Nanjing University. Lijian’s research interests include quantum optics, quantum information processing, coherent optical communications and interactions between light and quantum matter.