Prof. PAN Jianwei and his colleges from University of Science and Technology of China (USTC) of the Chinese Academy of Sciences (CAS) have achieved the experimental verification of distribution quantum phase estimation for the first time. This work was published on Nature Photonics.
Distributed metrology is a key tool to measure several locations from remote simultaneously with high precision, one typical task of which is the monitoring of stress field and temperature field of bridge and airplane.
In line with the development of quantum technology, metrology also entered quantum era. When targeting on the measurement of multiple parameters distributed in space, distributed quantum metrology can enhance the sensitivity of measurements beyond the classical limits.
However, the researchers are wondering how to achieve entangled states for optimal precision of multiparameter measurement, which was known as the ultimate Heisenberg limit.
In this study, Prof. PAN's team designed the optimal measurement scheme using entangled photons, and demonstrated measurement of individual phase shifts and their average. The precision went beyond the theory limit of classical sensor.
By considering both photon entanglement and coherence, Prof. PAN's team further demonstrated linear combination of multiple phase shifts with the total number of parameters to measure up to 21. This combined scheme both enlarged the number of measurable parameters and enhanced the precision compared with using photon entanglement only.
This study assesses the precision of measurement in different entanglement strategies and provided the verification of the benefit of entanglement and coherence for distributed quantum metrology. It lays a foundation for future application of high-precision distributed quantum metrology.