Quantum entangled, or "Schrördinger cat", states 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. In a paper recently published in Science, Joe Fitzsimons, Andrew Briggs and John Morton of this department, and co-workers, compared the magnetic field sensitivity of a classical (unentangled) system with that of a 10-qubit entangled state, realised by nuclear spins in a highly symmetric molecule (comprising nine 1H nuclei around a central 31P). They observed a 9.4-fold quantum enhancement in the sensitivity to an applied field for the entangled system and showed that this spin-based approach can scale favorably compared to approaches where qubit loss is prevalent. This result demonstrates a method for magnetic field sensing technology, based on quantum entanglement.

Quantum entangled, or "Schrördinger cat", states 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. In a paper recently published in Science, Joe Fitzsimons, Andrew Briggs and John Morton of this department, and co-workers, compared the magnetic field sensitivity of a classical (unentangled) system with that of a 10-qubit entangled s