Trapped Rydberg ions are a novel system for quantum computation and quantum simulation. They combine the key strengths of Rydberg atoms and trapped ion quantum processors in one technology. From Rydberg atoms they inherit the strong dipolar interaction, with trapped ions they share the full quantum information toolbox. This technology promises to speed up trapped ion entanglement operations and make them available in large ion crystals.

Distant entangled particles are an important resource in quantum information. Entangled photons can be easily sent to distant locations for applications like quantum teleportation and quantum communication.

Trapped Ions are one of the most mature implementation for realizing a quantum computer. Here, ions are confined in a linear Paul trap and are cooled with laser light. The ions repel each other due to Coulomb interaction and crystallize in linear, 2d, or 3d structures depending on the number of ions and the shape of the confining potential. Thanks to the ultra-high vacuum conditions and the deep confining potential, the ions are well isolated from the environment and stay trapped for days. Quantum information is encoded in the ions’ electronic states and is manipulated by laser or microwave pulses. Also, the ions in the trap can exchange quantum information via their common motion, which makes it possible to perform quantum calculations on an ion string.