Quantum walks of a phonon in trapped ions

Understand

Propagation and interference of quantum-mechanical particles comprise an important part of elementary processes in quantum physics, and their essence can be modeled using a quantum walk, a mathematical concept that describes the motion of a quantum-mechanical particle among discretized spatial regions.

• Here we report the observation of the quantum walks of a phonon, a vibrational quantum, in a trapped-ion crystal.
• By employing the capability of preparing and observing a localized wave packet of a phonon, the propagation of a single radial local phonon in a four-ion linear crystal is observed with single-site resolution.
• The results show an agreement with numerical calculations, indicating the predictability and reproducibility of the phonon system.