Aharonov–Bohm effect in the tunnelling of a quantum rotor in a linear Paul trap

Quantum tunnelling is a common fundamental quantum mechanical phenomenon that originates from the wave-like characteristics of quantum particles. Although the quantum tunnelling effect was first observed 85 years ago, some questions regarding the dynamics of quantum tunnelling remain unresolved. Here we realize a quantum tunnelling system using two-dimensional ionic structures in a linear Paul trap. We demonstrate that the charged particles in this quantum tunnelling system are coupled to the vector potential of a magnetic field throughout the entire process, even during quantum tunnelling, as indicated by the manifestation of the Aharonov–Bohm effect in this system. The tunnelling rate of the structures periodically depends on the strength of the magnetic field, whose period is the same as the magnetic flux quantum φ 0 through the rotor [(0.99±0.07) × φ 0 ]. In the Aharonov–Bohm effect, coupling between an electromagnetic field potential and a charged particle’s wave function introduces a phase to the particle. By realizing a quantum tunnelling system of three ions in a linear Paul trap, Noguchi et al . demonstrate this effect via the particle tunnelling.