Magnetic Field Sensing Beyond the Standard Quantum Limit Using 10-Spin NOON States
Jonathan A. Jones,1
Steven D. Karlen,2
Joseph Fitzsimons,2,3
Arzhang Ardavan,1
Simon C. Benjamin,2,4
G. Andrew D. Briggs,2
John J. L. Morton1,2,*
Quantum entangled states can be very delicate and easily perturbed
by their external environment. This sensitivity can be harnessed
in measurement technology to create a quantum sensor with a
capability of outperforming conventional devices at a fundamental
level. We compared the magnetic field sensitivity of a classical
(unentangled) system with that of a 10-qubit entangled state,
realized by nuclei in a highly symmetric molecule. We observed
a 9.4-fold quantum enhancement in the sensitivity to an applied
field for the entangled system and show that this spin-based
approach can scale favorably as compared with approaches in
which qubit loss is prevalent. This result demonstrates a method
for practical quantum field sensing technology.
2 Department of Materials, Oxford University, Oxford OX1 3PH, UK.
3 Institute of Quantum Computing, University of Waterloo, Waterloo, ON, N2L 3G1, Canada.
4 Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, 117543 Singapore.
* To whom correspondence should be addressed. E-mail: john.morton{at}materials.ox.ac.uk
