Enhancing Quantum Metrology by Quantum Resonance Dynamics

TL;DR

This paper introduces a novel quantum metrology protocol leveraging quantum resonance dynamics in spin systems, achieving Heisenberg-limited precision while overcoming common obstacles like entangled state preparation and noise sensitivity.

Contribution

It proposes a new metrology method using periodically driven spin systems tuned to quantum resonances, enabling high-precision measurements without requiring entangled state preparation.

Findings

Quantum Fisher information scales quadratically with the number of spins and time.

The protocol achieves Heisenberg scaling even under Markovian noise.

Experimental feasibility of the proposed method is demonstrated.

Abstract

Quantum effects in metrology can in principle enhance measurement precision from the so-called standard quantum limit to the Heisenberg Limit. Further advancements in quantum metrology largely rely on innovative metrology protocols that can avoid a number of known obstacles, including the challenge of preparing entangled states with sufficient fidelity, the readout noise in measuring highly entangled states, and no-go theorems for quantum metrology under noisy environments. In this Letter, exploiting some peculiar but experimentally feasible dynamical features of a collection of spins with all-to-all time-periodic interactions, we propose a metrology protocol that can circumvent all the three mentioned obstacles and yet still make good use of time as a resource for metrology. Specifically, by mapping the dynamics of such a periodically driven spin system to that of a paradigm of quantum chaos but tuned to some high-order quantum resonance, it is shown that a simple $SU(2)$ coherent state can, after evolving to highly entangled states in the ensuing dynamics, be dynamically brought back to the same initial coherent state. The associated quantum Fisher information is found to exhibit quadratic scaling with both the number of spins and the duration of the metrology protocol. The achieved Heisenberg scaling can also largely survive in the presence of Markovian noise. Representing a previously unknown strategy for quantum metrology, the protocol proposed here can be tested on available experimental platforms.