Demonstration of Entanglement-Enhanced Phase Estimation in Solid

TL;DR

This paper demonstrates, for the first time at room temperature in a solid-state system, that entanglement can enhance phase estimation precision using nitrogen-vacancy centers in diamond, confirming quantum metrology advantages.

Contribution

It provides the first experimental demonstration of entanglement-enhanced phase estimation in a solid-state system at room temperature.

Findings

Uncertainty reduced with entanglement resource

Super-resolving phase measurement achieved

Experimental data confirms theoretical predictions

Abstract

Precise parameter estimation plays a central role in science and technology. The statistical error in estimation can be decreased by repeating measurement, leading to that the resultant uncertainty of the estimated parameter is proportional to the square root of the number of repetitions in accordance with the central limit theorem. Quantum parameter estimation, an emerging field of quantum technology, aims to use quantum resources to yield higher statistical precision than classical approaches. Here, we report the first room-temperature implementation of entanglement-enhanced phase estimation in a solid-state system: the nitrogen-vacancy centre in pure diamond. We demonstrate a super-resolving phase measurement with two entangled qubits of different physical realizations: an nitrogen-vacancy centre electron spin and a proximal ${}^{13}$C nuclear spin. The experimental data shows clearly the uncertainty reduction when entanglement resource is used, confirming the theoretical expectation. Our results represent an elemental demonstration of enhancement of quantum metrology against classical procedure.