Magnetic field sensors using 13-spin cat states

Abstract

Measurement devices could benefit from entangled correlations to yield a measurement sensitivity approaching the physical Heisenberg limit. Building upon previous magnetometric work using pseudo-entangled spin states in solution-state NMR, we present two conceptual advancements to better prepare and interpret the pseudo-entanglement resource as well as the use of a 13-spin cat state to measure the local magnetic field with a sensitivity beyond the standard quantum limit.

6 pages, 5 figures; v2: corrected figure 3, expanded conclusion, simplified explanation of equation 2; v3: accepted version