Ramsey interferometry and radical pair mechanism for magnetic field sensing: A comparative study
Xiaoyu Chen, Haibin Liu, Jianming Cai, Phys. Lett. A 592, 131928 (2026)
The radical pair mechanism (RPM) in the chemical magnetic compass model is considered to be one of the most promising candidates for avian magnetic navigation, with the quantum needle phenomenon further boosting the navigation precision to a new high level. It is well known that there are also a variety of methods in the field of magnetic field sensing in the laboratory, e.g. the Ramsey protocol of NV centers in diamond. Here, we compare the RPM model and the Ramsey-like model under laboratory conditions and under in vivo conditions, respectively. The results are both surprising and reasonable. Under laboratory conditions, if we have precise control over time and a reasonably accurate prior knowledge of the magnetic field direction, the Ramsey-like model will outperform the RPM model. However, when such information is unavailable, as under in vivo conditions, the RPM model stands out, offering enhanced practicality at the cost of reduced accuracy.
