Trapped Ions

Ions can be trapped by electromagnetic forces, either in an oscillating quadripole electric field 1 or in a combination of an electric and a magnetic field. While the ions have different internal states, they are also subject to vibrational modes. Two internal states can be selected to from a qubit, while the vibrational modes can be used as a mediator for the interaction between the ions. By properly choosing the frequency and length of laser pulses, the ions can be entangled, and circuit gates can be implemented. See also the section entanglement of trapped ions.

  • seminal paper by Cirac & Zoller [26]

1

The principle of the Paul trap is nicely illustrated by this rotating saddle video! The trajectories of ions in a Paul trap describe Lissajous curves.

Complements: An Introduction » Quantum Computing » Realization