Quantum metrology at the Heisenberg limit with the presence of independent dephasing

TL;DR

This paper demonstrates that Heisenberg-limited quantum metrology can be achieved even with independent dephasing by exploiting entanglement properties and collective noise, enabling robust high-precision measurements.

Contribution

It introduces a protocol for Heisenberg-limited sensing under independent dephasing, leveraging entanglement to outperform classical states despite environmental noise.

Findings

Heisenberg limit is attainable with independent dephasing.

Entanglement decays faster under collective noise, aiding detection.

Sensitivity at the Heisenberg limit is achievable for Markovian collective dephasing.

Abstract

The Heisenberg limit is the superior precision available by entanglement sensors. However, entanglementis fragile against dephasing, and there is no known quantum metrology protocol that can achieve Heisenberg limited sensitivity with the presence of independent dephasing. Here, we show that the Heisenberg limit is attainable under the effect of independent dephasing under conditions where the probe qubits decohere due to both target fields and local environments. To detect the target fields, we exploit the entanglement properties to decay much faster than the classical states due to collective noise while most of the previous schemes use a coherent phase shift from the target fields. Actually, if the temporally fluctuating target fields behave as Markovian collective dephasing, we can estimate the collective dephasing rate with a sensitivity at the Heisenberg limit under the effect of independent dephasing. Our work opens the possibility for robust Heisenberg-limited metrology.