Physics Letters A, 523, 129795 (2024)
Enhanced super-Heisenberg scaling precision by nonlinear coupling and postselection
Qin Lupei1,2,*, Li Jialin1,2, Niu Yazhi1,2 and Li Xin-Qi3,*
1 Center for Joint Quantum Studies and Department of Physics, School of Science, Tianjin University, Tianjin 300072, China.
2 School of Science, Tianjin University, Tianjin 300072, China.
3 Research Center for Quantum Physics and Technologies, School of Physical Science and Technology, Inner Mongolia University, Hohhot 010021, China.
* qinlupei@tju.edu.cn, xinqi.li@imu.edu.cn
Abstract
In quantum metrology, the famous result of Heisenberg limit, scaling as 1/N (with N the number of probes), can be surpassed by considering nonlinear coupling measurement. In this work, we consider the most practice- relevant quadratic nonlinear coupling and show that the metrological precision can be enhanced from the 1/N super-Heisenberg scaling to 1/N2, by simply employing a preand post-selection (PPS) strategy, but not using any expensive quantum resources such as quantum entangled state of probes.
