Quantum walks of a phonon in trapped ions

TL;DR

This paper reports the experimental observation of quantum walks of a phonon in a trapped-ion system, demonstrating controlled phonon propagation with potential applications in quantum simulation and computation.

Contribution

First observation of phonon quantum walks in a trapped-ion crystal with single-site resolution, advancing quantum walk experiments and phonon-based quantum information processing.

Findings

Phonon quantum walks observed in a four-ion crystal.

Propagation matches numerical predictions.

Potential for scalable quantum simulations and boson sampling.

Abstract

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. These characteristics may contribute advantageously in advanced experimental studies of quantum walks with large numbers of nodes, as well as realization of boson sampling and quantum simulation using phonons as computational resources.