Parameter estimation in a memory-assisted noisy quantum interferometry

TL;DR

This paper explores how memory effects in a multi-qubit system can slow entanglement decay, thereby preserving high-precision parameter estimation in noisy quantum interferometry, with implications for quantum sensing.

Contribution

It introduces the concept that memory effects can be harnessed to maintain sub shot-noise sensitivity in noisy quantum interferometry, providing theoretical analysis and calculations of quantum Fisher information.

Findings

Memory slows entanglement decay in noisy systems

Memory effects help retain sub shot-noise sensitivity

Quantum Fisher information bounds estimation precision

Abstract

We demonstrate that memory in an $N$-qubit system subjected to decoherence, is a potential resource for the slow-down of the entanglement decay. We show that this effect can be used to retain the sub shot-noise sensitivity of the parameter estimation in quantum interferometry. We calculate quantum Fisher information, which sets the ultimate bound for the precision of the estimation. We also derive the sensitivity of such a noisy interferometer, when the phase is either estimated from the measurements of the population imbalance or from the one-body density.