Ion Coulomb crystals: an exotic form of condensed matter

TL;DR

Ion Coulomb crystals are ordered structures of laser-cooled ions in traps, offering a tunable platform to study strongly correlated phases of matter and quantum phenomena at low temperatures.

Contribution

This review synthesizes the theoretical and experimental understanding of ion Coulomb crystals, highlighting their properties and potential for exploring condensed matter physics.

Findings

Crystalline structures emerge from Coulomb interactions and trapping potentials.

Ion crystals can be manipulated and imaged with high precision.

They serve as a platform for studying quantum many-body phenomena.

Abstract

Ion Coulomb crystals are ordered structures formed by laser-cooled ions in traps that are characterized by interparticle distances of several micrometers and energy scales on the order of $\mu$eV. Their crystalline structure emerges from the interplay between Coulomb repulsion and the external confining potential, which can be readily tuned. Moreover, individual ions can be precisely manipulated with lasers and imaged via resonance fluorescence. These unusual and unique properties make ion crystals a powerful platform for studying phases of matter in the strongly correlated regime and at low temperatures where their dynamics is manifestly quantum mechanical. This review examines the theoretical framework and experimental characterization of ion Coulomb crystals from a condensed-matter perspective. We discuss their dynamical and thermodynamic properties in one, two, and three dimensions, and review recent investigations into their out-of-equilibrium behavior. We provide outlooks on future directions for exploring novel condensed matter phenomena with trapped ion crystals, as well as for exploiting these features for scientific and technical applications.