Recovering optimal precision in quantum sensing with time domain imperfections

TL;DR

This paper develops a control strategy for quantum sensing that compensates for time domain imperfections, achieving near-optimal precision limits even with real-world control errors, validated through NMR experiments.

Contribution

It introduces a novel control approach that maintains quantum sensing precision in the presence of time domain imperfections, outperforming control-free methods.

Findings

Outperforms control-free strategies in frequency estimation

Recovers the Heisenberg limit with small intrinsic error

Validated through experiments on an NMR platform

Abstract

Quantum control plays a crucial role in enhancing precision scaling for quantum sensing. However, most existing protocols require perfect control, even though real-world devices inevitably have control imperfections. Here, we consider a fundamental setting of quantum sensing with time domain imperfections, where the duration of control pulses and the interrogation time are all subject to uncertainty. Under this scenario, we investigate the task of frequency estimation in the presence of a non-Markovian environment. We design a control strategy and prove that it outperforms any control-free strategies, recovering the optimal Heisenberg limit up to a small error term that is intrinsic to this model. We further demonstrate the advantage of our control strategy via experiments on a nuclear magnetic resonance (NMR) platform. Our finding confirms that the advantage of quantum control in quantum sensing persists even in the presence of imperfections.