Observation of ground-state quantum beats in atomic spontaneous emission

TL;DR

This paper demonstrates ground-state quantum beats in atomic spontaneous emission, revealing spontaneously generated coherence through intensity autocorrelation, and implements a quantum eraser to manipulate quantum superpositions.

Contribution

It presents the first observation of ground-state quantum beats in spontaneous emission and introduces a quantum eraser technique to control quantum coherence.

Findings

Quantum beats are observed in intensity autocorrelation.

Spontaneously generated coherence is evidenced.

A quantum eraser is realized in atomic emission.

Abstract

We report ground-state quantum beats in spontaneous emission from a continuously driven atomic ensemble. Beats are visible only in an intensity autocorrelation and evidence spontaneously generated coherence in radiative decay. Our measurement realizes a quantum eraser where a first photon detection prepares a superposition and a second erases the "which-path" information in the intermediate state.