| A single 9Be+ ion confined in an rf (Paul) trap may be used to realize two of the simplest quantum systems: the two-level system and the harmonic oscillator. The two-level system is comprised of two, ground-state hyperfine electronic levels. The trapping potential is harmonic, to a high degree of approximation, and so the ion's motion is that of a three-dimensional harmonic oscillator.; By coupling the ion's motional and electronic degrees of freedom, we can engineer entanglement between these systems. This allows us to study quantum mechanics, with all its pecularities, in a well-controlled environment. For example, we can study the interactions of superposition states with the ion's environment, leading to a destruction of quantum superpositions. Furthermore, this system, when scaled up to several ions, may allow us to construct a simple “quantum computer,” which promises exponential speed-up over any possible classical computer for some computational problems. Towards this goal, we have cooled two, trapped ions to their ground state of collective motion and deterministically created entanglement of their electronic degrees of freedom, with their joint motion serving to transfer this entanglement between them. |
