Dynamic formation of Rydberg aggregates at off-resonant excitation

TL;DR

This paper investigates how off-resonant laser excitation induces dynamic, asymmetric Rydberg atom aggregates with properties dependent on laser detuning, enabling novel quantum gate implementations.

Contribution

It reveals the formation of non-localized Rydberg aggregates driven by off-resonant excitation and demonstrates their application in implementing a three-atom quantum gate.

Findings

Aggregates extend over the entire ensemble volume.

Spatial correlations depend on laser detuning and interaction potential.

A continuous-wave off-resonant laser can create specific atomic arrangements.

Abstract

The dynamics of a cloud of ultra-cold two-level atoms is studied at off-resonant laser driving to a Rydberg state. We find that resonant excitation channels lead to strongly peaked spatial correlations associated with the buildup of asymmetric excitation structures. These aggregates can extend over the entire ensemble volume, but are in general not localized relative to the system boundaries. The characteristic distances between neighboring excitations depend on the laser detuning and on the interaction potential. These properties lead to characteristic features in the spatial excitation density, the Mandel $Q$ parameter, and the total number of excitations. As an application an implementation of the three-atom CSWAP or Fredkin gate with Rydberg atoms is discussed. The gate not only exploits the Rydberg blockade, but also utilizes the special features of an asymmetric geometric arrangement of the three atoms. We show that continuous-wave off-resonant laser driving is sufficient to create the required spatial arrangement of atoms out of a homogeneous cloud.