Quantum imaging by coherent enhancement

TL;DR

This paper demonstrates that utilizing long coherence times in quantum systems allows for imaging with a resolution that scales at the Heisenberg limit, significantly surpassing classical methods.

Contribution

The authors introduce a quantum imaging procedure that exploits coherence to achieve Heisenberg-limited resolution in determining a two-level system's position.

Findings

Position estimation errors scale as 1/t at the Heisenberg limit.

Quantum coherence enhances imaging resolution beyond classical limits.

The method provides an optimal quadratic improvement over classical scaling.

Abstract

Conventional wisdom dictates that to image the position of fluorescent atoms or molecules, one should stimulate as much emission and collect as many photons as possible. That is, in this classical case, it has always been assumed that the coherence time of the system should be made short, and that the statistical scaling $\sim1/\sqrt{t}$ defines the resolution limit for imaging time $t$. However, here we show in contrast that given the same resources, a long coherence time permits a higher resolution image. In this quantum regime, we give a procedure for determining the position of a single two-level system, and demonstrate that the standard errors of our position estimates scale at the Heisenberg limit as $\sim 1/t$, a quadratic, and notably optimal, improvement over the classical case.