Spontaneous decay induced quantum dynamics in Rydberg blockaded {\Lambda}-type atoms

TL;DR

This paper develops an efficient model for Rydberg-atom ensembles with spontaneous decay, revealing complex spectral features and relaxation dynamics relevant for quantum information transfer.

Contribution

It introduces a computationally-efficient approach to analyze Rydberg-Λ-type atom ensembles with decay, enabling practical experimental analysis and understanding of spectral and relaxation behaviors.

Findings

Quasi-steady-state power spectrum with multiple sidebands

Time-dependent sideband heights influenced by atomic relaxation

Analytical expression for relaxation time as a function of atom number

Abstract

Strongly Rydberg-blockaded two-level atoms form a Rydberg superatom, which is excited only to a collective symmetrical Dicke state. However, emerging often in the alkali-earth atoms, the spontaneous decay from the Rydberg state to an additional pooling state renders the ensemble no longer a closed superatom. Herein we present a computationally-efficient model to characterize the interaction between a fully Rydberg-blockaded ensemble of $N$ $\Lambda$-type three-level atoms and a strong probe light field in a coherent state. The model enables us to achieve a decomposition of the coupled dynamics in the strong field limit, which significantly reduces the complexity of computing the $N$-body system evolution and paves a way for practical analysis in experiments. A quasi-steady-state power spectrum with multiple sidebands is found in the scattered field. The relative heights of the sidebands show a time dependence determined by the atomic relaxation, which illuminates potential applications of using the system in information transfer of quantum networks. With negligible dissipative flipping to the unsymmetrical states, the atomic relaxation time indicating a linearly increasing pooling state fraction is derived analytically as a function of the atom number.