Domain formation and structural stabilities in mixed-species Coulomb crystals induced by sympathetically cooled highly charged ions

TL;DR

This study investigates how highly charged ions embedded in Coulomb crystals influence the structure, stability, and dynamics of the crystals, providing insights relevant for quantum technologies and fundamental physics research.

Contribution

It offers new experimental and simulation insights into the formation, stability, and phase behavior of mixed-species Coulomb crystals with highly charged ions.

Findings

HCIs form superlattices within Coulomb crystals

Different reordering rates and melting points observed across domains

Simulations accurately reproduce experimental dynamics

Abstract

There is a growing interest in high-precision spectroscopy and frequency metrology for fundamental studies using sympathetically cooled highly charged ions (HCIs) embedded in Coulomb crystals of laser-cooled ions. In order to understand how their strong repulsion affects the crystal structure and dynamics, we study the thermal motion and rearrangement of small mixed linear and homogeneous crystals by both measurements and simulations. Co-crystallized HCIs form superlattices and divide the crystal into domains, where different reordering rates, melting points and localized phase transitions are observed due to decoupling of motional modes across boundaries. These results improve our understanding of homogeneous and inhomogeneous ion strings over a wide range of charge-to-mass ratios. This allows us to test our own simulations of the dynamic behavior of ion strings and gives us confidence in their suitability for applications related to quantum simulation as well as computing and the search for new physics.