Heisenberg-Limited Waveform Estimation with Solid-State Spins in Diamond

TL;DR

This paper demonstrates Heisenberg-limited quantum waveform estimation using diamond spins at room temperature, significantly surpassing classical limits with practical quantum techniques and enhanced sensitivity.

Contribution

It introduces a novel quantum difference detection method for waveform estimation with solid-state spins, achieving Heisenberg-limited precision under ambient conditions.

Findings

Reduced estimation error by over 5 dB below standard quantum limit

Enhanced dynamic range and sensitivity by an order of magnitude

Achieved quantum-limited estimation with fewer resources than classical methods

Abstract

The newly established Heisenberg limit in arbitrary waveform estimation is quite different with parameter estimation and shows a unique characteristic of a future quantum version of oscilloscope. However, it is still a non-trivial challenge to generate a large number of exotic quantum entangled states to achieve this quantum limit. Here, by employing the time-domain quantum difference detection method, we demonstrate Heisenberg-limited waveform quantum estimation with diamond spins under ambient condition in the experiment. Periodic dynamical decoupling is applied to enhance both the dynamic range and sensitivity by one order of magnitude. Using this quantum-enhanced estimation scheme, the estimation error of an unknown waveform is reduced by more than $5$ dB below the standard quantum limit with $N\sim{\text{2}} \times {\text{1}}{{\text{0}}^3}$ resources, where more than ${1 \times {\text{1}}{{\text{0}}^5}}$ resources would be required to achieve a similar error level using classical detection. This work provides an essential step towards realizing quantum-enhanced structure recognition in a continuous space and time.