Echoed Random Quantum Metrology

TL;DR

This paper introduces a robust, scalable quantum metrology protocol using echoed random processes and Kerr nonlinear modes, achieving near-Heisenberg sensitivity without complex quantum control.

Contribution

It presents a novel, hardware-efficient method for quantum-enhanced metrology that does not require precise quantum state preparation or control optimization.

Findings

Achieves sensitivity close to the Heisenberg limit.

Robust against control fluctuations and photon loss.

Applicable to both bosonic and qubit platforms.

Abstract

Quantum metrology typically demands the preparation of exotic quantum probe states, such as entangled or squeezed states, to surpass classical limits. However, the need for carefully calibrated system parameters and finely optimized quantum controls imposes limitations on scalability and robustness. Here, we circumvent these limitations by introducing an echoed random process that achieves sensitivity approaching the Heisenberg limit while remaining blind to the random probe state. We demonstrate that by simply driving a Kerr nonlinear mode with random pulses, the emergence of sub-Planck phase-space structures grants high sensitivity, eliminating the need for complex quantum control. The protocol is statistically robust, yielding high performance across broad driving parameter ranges while exhibiting resilience to control fluctuations and photon loss. Broadly applicable to both bosonic and qubit platforms, our work reveals a practical, hardware-efficient, scalable, and optimization-free route to quantum-enhanced metrology in high-dimensional Hilbert spaces.