Intercombination Effects in Resonant Energy Transfer

TL;DR

This paper explores how weakly allowed intercombination transitions influence resonant energy transfer in Rydberg atoms, revealing effects on long-range interactions and spin dynamics in multi-atom systems.

Contribution

It demonstrates the impact of intercombination effects on energy transfer and spin chain behavior in Rydberg atoms, linking atomic coupling breakdown to many-body spin phenomena.

Findings

Weakly allowed spin transitions affect Rydberg atom interactions.

Resonant spin hopping occurs in spin chains with engineered energy levels.

Breakdown of LS-coupling maps onto spatial spin-orbital separation.

Abstract

We investigate the effect of intercombination transitions in excitation hopping processes such as those found in F\"orster resonance energy transfer. Taking strontium Rydberg states as our model system, the breakdown of $LS$-coupling leads to weakly allowed transitions between Rydberg states of different spin quantum number. We show that the long-range interactions between two Rydberg atoms can be affected by these weakly allowed spin transitions, and the effect is greatest when there is a near-degeneracy between the initial state and a state with a different spin quantum number. We also consider a case of four atoms in a spin chain, and show that a spin impurity can resonantly hop along the chain. By engineering the many-body energy levels of the spin-chain, the breakdown of $LS$ coupling due to inter-electronic effects in individual atoms can be mapped onto a spatial separation of the total spin and the total orbital angular momentum along the spin chain.