Manya and Colleagues Implement Simplified Observables for Floquet Time Crystal Sensing

M. A. Manya and colleagues from University of Federal Fluminense present a new approach to optimise quantum sensing protocols, achieving sensitivity close to the theoretical limit imposed by the quantum Fisher information. The approach shows that while the symmetric logarithmic derivative operator theoretically achieves this optimal sensitivity, its complexity hinders practical implementation. Focusing on a Floquet time crystal as an ac field sensor, they reveal that this complex operator can be effectively approximated by simpler, experimentally accessible observables like spin magnetization or parity. Validated through simulations using a nuclear magnetic resonance system, the findings offer a…