Rydberg Macrodimers: Diatomic molecules on the micrometer scale

TL;DR

This paper reviews the field of Rydberg macrodimers, highlighting their unique micrometer-scale bond lengths, potential for quantum control, and their relevance for quantum computing, including new insights into molecular interactions and many-body phenomena.

Contribution

It provides a comprehensive overview of Rydberg macrodimers, including recent experimental findings and introduces new data on their interactions and many-body effects.

Findings

Rydberg macrodimers have micrometer-scale bond lengths.

Spectroscopic studies achieve high accuracy, benchmarking Rydberg interactions.

Observation of a Rydberg blockade-like phenomenon at the molecular level.

Abstract

Controlling molecular binding at the level of single atoms is one of the holy grails of quantum chemistry. Rydberg macrodimers -- bound states between highly excited Rydberg atoms -- provide a novel perspective in this direction. Resulting from binding potentials formed by the strong, long-range interactions of Rydberg states, Rydberg macrodimers feature bond lengths in the micrometer regime, exceeding those of conventional molecules by orders of magnitude. Using single-atom control in quantum gas microscopes, the unique properties of these exotic states can be studied with unprecedented control, including the response to magnetic fields or the polarization of light in their photoassociation. The high accuracy achieved in spectroscopic studies of macrodimers makes them an ideal testbed to benchmark Rydberg interactions, with direct relevance to quantum computing and information protocols where these are employed. This review provides a historic overview and summarizes the recent findings in the field of Rydberg macrodimers. Furthermore, it presents new data on interactions between macrodimers, leading to a phenomenon analogous to Rydberg blockade at the level of molecules, opening the path towards studying many-body systems of ultralong-range Rydberg molecules.