On‐demand entanglement generation using dynamic single‐electron sources

We review our recent proposals for the on‐demand generation of entangled few‐electron states using dynamic single‐electron sources. The generation of entanglement can be traced back to the single‐electron entanglement produced by quantum point contacts (QPCs) acting as electronic beam splitters. The coherent partitioning of a single electron leads to entanglement between the two outgoing arms of the QPC. We describe our various approaches for generating and certifying entanglement in dynamic electronic conductors and we quantify the influence of detrimental effects such as finite electronic temperatures and other dephasing mechanisms. The prospects for future experiments are discussed and possible avenues for further developments are identified. (a) The coherent partitioning of a single electron on a QPC leads to entanglement between the outgoing arms. The entanglement can be detected using two copies of the state. (b) A time‐bin entangled state is generated by partitioning two electrons on a QPC followed by projection onto the subspace with one electron in each arm. The two‐electron entanglement is due to the entanglement of the individual single‐electron states. In both panels, circles represent single‐electron sources and squares represent detectors. Entanglement is not only a very counter‐intuitive feature of quantum mechanics but also a resource for tasks in quantum information with promising applications in encryption. Hofer et al. review their recent work on entanglement mediated by single electrons that are emitted into one‐dimensional waveguides in a controlled manner. Treating these works on equal footing, the authors present a unified picture of the origin and manipulation of entanglement in these promising systems