Simple implementation of a quantum search with trapped ions

Abstract

We propose an ion-trap implementation of Grover's quantum search algorithm for an unstructured database of arbitrary length $N$. The experimental implementation is appealingly simple because the linear ion trap allows for a straightforward construction, in a single interaction step and without a multitude of Hadamard transforms, of the reflection operator, which is the engine of the Grover algorithm. Consequently, a dramatic reduction in the number of the required physical steps takes place, to just $O(\sqrt{N})$, the same as the number of mathematical steps. The proposed setup allows for demonstration of both the original (probabilistic) Grover search and its deterministic variation, and is remarkably robust to imperfections in the register initialization.