Speaker
Description
Understanding how strongly interacting particles self-organize in confined geometries is central to both fundamental physics and the development of controllable quantum systems. Two-dimensional Coulomb crystals of trapped ions provide an ideal platform for this purpose since their confinement can be precisely tuned, and they are considered one of the most promising routes toward scaling up ion-based quantum computers.
We report on two structural effects observed in such crystals. First, we investigate orientational melting, a transition specific to mesoscopic two-dimensional systems in which ions lose angular order while remaining radially localized. This transition, strongly dependent on particle number, can be suppressed or enhanced by modifying the trap geometry or introducing impurities. Second, we study structural bistability and show how configuration changes can emulate molecular isomerization. Using Monte Carlo simulations, we map the potential energy surface of a six-ion system and identify a double-well structure, revealing two coexisting metastable isomers. Experimentally, we monitor the occupation probability of each isomer and extract relaxation dynamics with sub-millisecond resolution.
Furthermore, we will present the perspective of integrating two-dimensional Coulomb crystals into a bow-tie cavity. Unlike Fabry–Perot geometries, this design ensures optimal collective coupling between the entire ion crystal and an optical mode, while also enabling the creation of a deep optical potential to trap crystals in a static configuration free of micromotion. Such a hybrid electro-optical trap will make it possible to reach lower temperatures, paving the way to study the role of quantum fluctuations in structural transitions and the creation of a quantum superposition of crystal configurations.
