Observation of collective excitation of two individual atoms in the Rydberg blockade regime

TL;DR

This paper experimentally demonstrates the Rydberg blockade between two individual atoms separated by 4 micrometers, revealing collective excitation behavior and entanglement, advancing quantum information processing with neutral atoms.

Contribution

It provides the first experimental observation of collective excitation and entanglement in two atoms within the Rydberg blockade regime at this separation.

Findings

Successful demonstration of Rydberg blockade at 4 μm separation.

Observation of enhanced single-atom excitation due to collective behavior.

Evidence of entangled state formation between two atoms.

Abstract

The dipole blockade between Rydberg atoms has been proposed as a basic tool in quantum information processing with neutral atoms. Here we demonstrate experimentally the Rydberg blockade of two individual atoms separated by 4 $\mu$m. Moreover, we show that, in this regime, the single atom excitation is enhanced by a collective two-atom behavior associated with the excitation of an entangled state. This observation is a crucial step towards the deterministic manipulation of entanglement of two or more atoms using the Rydberg dipole interaction.