2003/06/30 by JM Geremia, John K. Stockton, Andrew C. Doherty +1 · 1 citation
Physics and Astronomy · #quant-ph
paper · pdf · doi:10.1103/physrevlett.91.250801
published as Phys. Rev. Lett. 91, 250801 (2003) · More details are available at http://minty.caltech.edu/Ensemble
arxiv created 2003/12/21 · arxiv updated 2009/12/01
The shot-noise detection limit in current high-precision atomic magnetometry is a manifestation of quantum fluctuations that scale as the square root of N in an ensemble of N particles. However, there is a general expectation that the reduced projection noise provided by conditional spin-squeezing could be exploited to surpass the conventional shot-noise limit. We show that continuous measurement coupled with quantum Kalman filtering provides an optimal procedure for magnetic detection limits that scale with 1/N, the Heisenberg squeezing limit. Our analysis demonstrates the importance of optimal estimation procedures for high bandwidth precision magnetometry.