Ramsey Interferometry in Correlated Quantum Noise Environments

TL;DR

This paper investigates how correlated quantum noise affects the precision of Ramsey interferometry, revealing that quantum correlations can significantly increase uncertainty and hinder super-classical scaling in quantum sensing.

Contribution

It provides a quantitative analysis of correlated quantum noise impacts on frequency estimation, highlighting the limitations imposed by quantum bath-induced entanglement.

Findings

Correlated quantum noise can exponentially increase measurement uncertainty with the number of probes.

Classical correlations can be exploited to reduce uncertainty, unlike quantum correlations.

Quantum noise from vibrational modes can prevent super-classical scaling in ion-based sensors.

Abstract

We quantify the impact of spatio-temporally correlated Gaussian quantum noise on frequency estimation by Ramsey interferometry. While correlations in a classical noise environment can be exploited to reduce uncertainty relative to the uncorrelated case, we show that quantum noise environments with frequency asymmetric spectra generally introduce additional sources of uncertainty due to uncontrolled entanglement of the sensing system mediated by the bath. For the representative case of collective noise from bosonic sources, and experimentally relevant collective spin observables, we find that the uncertainty can increase exponentially with the number of probes. As a concrete application, we show that correlated quantum noise due to a lattice vibrational mode can preclude superclassical precision scaling in current amplitude sensing experiments with trapped ions.