English

Demonstration of a free space rubidium atomic clock with noise below the quantum projection limit

Quantum Physics 2020-07-29 v1

Abstract

A technique is demonstrated that allows free space atomic fountain clocks and interferometers to utilize optical cavity generated spin-squeezed states with over 390000390\,000 87Rb{}^{87}\text{Rb} atoms. Fluorescence imaging is used for population spectroscopy, after a free fall time of 4 milliseconds, to resolve a single-shot phase sensitivity of 814(61)814 (61) microradians, which is 5.8(0.6)5.8(0.6) decibels (dB) below the quantum projection limit. The dynamic range is observed to be 100 milliradians. When operating as a microwave atomic clock with 240000240\,000 atoms at a 3.6 ms Ramsey time, a single-shot fractional frequency stability of 8.4(0.2)×10128.4(0.2)\times10^{-12} is reported, 3.8(0.2)3.8(0.2) dB below the quantum projection limit.

Keywords

Cite

@article{arxiv.1912.10218,
  title  = {Demonstration of a free space rubidium atomic clock with noise below the quantum projection limit},
  author = {Benjamin K. Malia and Julián Martínez-Rincón and Yunfan Wu and Onur Hosten and Mark A. Kasevich},
  journal= {arXiv preprint arXiv:1912.10218},
  year   = {2020}
}