Morgan W. Mitchell

Institut de Ciències Fotòniques (ICFO)

Sensitive detection of magnetic fields has applications ranging from brain imaging to space exploration, and many technogologies have been developed for these many applications. Until now, all have been limited in sensitivity by the so-called “energy resolution limit,” which constrains the combined spatial, temporal, and field resolution of the sensor. The in-practice limit was suspiciously close to hbar, the fundamental constant that defines the scale of the quantum world. In 2020 we analyzed the energy resolution limit (Mitchell et al. Rev. Mod. Phys. 2020), and concluded that exotic sensor types could beat this “limit.” In 2022 we employed a spinor Bose-Einstein condensate, to do just that, beating all previous sensors by almost two orders of magnitude, and more importantly showing that quantum physics does not place a hard limit on the sensitivity of field measurements (Palacios et al. PNAS 2022).