Magnetic field sensing beyond the standard quantum limit using 10-spin NOON states

TL;DR

This paper demonstrates experimentally that 10-spin NOON states can surpass the standard quantum limit in magnetic field sensing, achieving nearly tenfold sensitivity enhancement using nuclear spins.

Contribution

It presents the first experimental realization of 10-spin NOON states for magnetic sensing, surpassing the standard quantum limit with improved scalability.

Findings

Achieved 9.4-fold sensitivity increase over single spins.

Demonstrated scalability advantages over systems with qubit loss.

Paved the way for enhanced quantum magnetic field sensors.

Abstract

The concept of entanglement, in which coherent quantum states become inextricably correlated, has evolved from one of the most startling and controversial outcomes of quantum mechanics to the enabling principle of emerging technologies such as quantum computation and quantum sensors. The use of entangled particles in measurement permits the transcendence of the standard quantum limit in sensitivity, which scales as N^1/2 for N particles, to the Heisenberg limit, which scales as N. This approach has been applied to optical interferometry using entangled photons and spin pairs for the measurement of magnetic fields and improvements on atomic clocks. Here, we demonstrate experimentally an 9.4-fold increase in sensitivity to an external magnetic field of a 10-spin entangled state, compared with an isolated spin, using nuclear spins in a highly symmetric molecule. This approach scales in a favourable way compared to systems where qubit loss is prevalent, and paves the way for enhanced precision in magnetic field sensing