We experimentally determine the coupling strength between two strongly coupled nanomechanical modes using a Ramsey-inspired technique optimized for signals as short as four fringes. The method is applied to precisely probe the change of the coupling rate induced by a modification of the microwave-cavity readout field. It opens a pathway towards sensing electrostatic field fluctuations approaching single-charge resolution.
@article{arxiv.2601.13415,
title = {Precise estimation of the coupling strength between two nanomechanical modes from four Ramsey fringes},
author = {Anh Tuan Le and Avishek Chowdhury and Hugo Ribeiro and Eva M. Weig},
journal= {arXiv preprint arXiv:2601.13415},
year = {2026}
}