Quantum metrology beyond the classical limit under the effect of dephasing

TL;DR

This paper proposes a quantum sensing scheme that maintains a 1/T uncertainty scaling over arbitrary times despite dephasing, surpassing classical limits by using teleportation to suppress local dephasing effects.

Contribution

It introduces a teleportation-based protocol that prevents correlation buildup with the environment, enabling sustained quantum sensitivity beyond classical and previous quantum limits.

Findings

Achieves 1/T uncertainty scaling under dephasing for arbitrary measurement times.

Uses one-way quantum computing teleportation to suppress local dephasing effects.

Potential to develop quantum sensors with sensitivities far exceeding classical sensors.

Abstract

Quantum sensors have the potential to outperform their classical counterparts. For classical sensing, the uncertainty of the estimation of the target fields scales inversely with the square root of the measurement time T. On the other hand, by using quantum resources, we can reduce this scaling of the uncertainty with time to 1/T. However, as quantum states are susceptible to dephasing, it has not been clear whether we can achieve sensitivities with a scaling of 1/T for a measurement time longer than the coherence time. Here, we propose a scheme that estimates the amplitude of globally applied fields with the uncertainty of 1/T for an arbitrary time scale under the effect of dephasing. We use one-way quantum computing based teleportation between qubits to prevent any increase in the correlation between the quantum state and its local environment from building up and have shown that such a teleportation protocol can suppress the local dephasing while the information from the target fields keeps growing. Our method has the potential to realize a quantum sensor with a sensitivity far beyond that of any classical sensor.