An N-atom Collective State Atomic Clock with Root-N Fold Increase in Effective Frequency and Root-N Fold Reduction in Fringe Width

TL;DR

This paper introduces a collective state atomic clock that achieves a -fold increase in effective frequency and a -fold reduction in fringe width by leveraging collective state interferences among N atoms, enhancing stability without entanglement.

Contribution

It presents a novel collective state atomic clock design that improves stability and frequency resolution through collective interference effects, avoiding entanglement.

Findings

Fringe width narrowed by  compared to conventional clocks

Detection efficiency increased, improving stability by up to tenfold

Effective -fold frequency increase achieved through collective states

Abstract

We describe a collective state atomic clock with Ramsey fringes narrowed by a factor of $\sqrt{N}$ compared to a conventional clock, N being the number of non-interacting atoms, without violating the uncertainty relation. This narrowing is explained as being due to interferences among the collective states, representing an effective $\sqrt{N}$ fold increase in the clock frequency, without entanglement. The detection process, which measures a collective state, can be used to increase the quantum efficiency of detection significantly, yielding a net improvement in stability by as much as a factor of 10.