Dephasing-assisted parameter estimation in the presence of dynamical decoupling

TL;DR

This paper demonstrates that dephasing noise, when combined with dynamical decoupling pulses, can enhance parameter estimation precision in atom interferometers by inducing spin squeezing and increasing quantum Fisher information, approaching the Heisenberg limit.

Contribution

It reveals that dephasing noise can be harnessed to improve quantum parameter estimation when combined with dynamical decoupling, reaching near Heisenberg-limited precision.

Findings

Dephasing noise induces spin squeezing that can be maximized with DD pulses.

DD pulses amplify quantum Fisher information by approximately N/2.

Enhanced PPE approaches the Heisenberg limit of 1/N under optimal conditions.

Abstract

We study the dephasing-assisted precision of parameter estimation (PPE) enhancement in atom interferometer under dynamical decoupling (DD) pulses. Through calculating spin squeezing (SS) and quantum Fisher information (QFI), we find that dephasing noise can improve PPE by inducing SS, and the DD pulses can maximize the improvement. It is indicated that in the presence of DD pulses, the dephasing-induced SS can reach the limit of \textquotedblleft one-axis twisting\textquotedblright\ model, $\xi^2\simeq N^{-2/3}$ with $\xi^2$ being the SS parameter and N the number of atoms. In particular, we find that the DD pulses can amplify the dephasing-induced QFI by a factor of $\simeq N/2$ compared with the noise-free case, which means that under the control of DD pulses, the dephasing noise can enhance the PPE to the scale of $\sqrt{2}/N$, the same order of magnitude of Heisenberg limit (1/N).