Towards entangled electrons

Willi-Hans Steeb, Yorick Hardy

Patrick P. Potts, David Dasenbrook, Christian Flindt

Abstract 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.

William D. Oliver

任宝藏, Hua Ming, Tao Li +2 more

We propose a different entanglement concentration protocol (ECP) for nonlocal N-electron systems in a partially entangled Bell-type pure state using the CNOT gates and the projection measurements on an additional electron. For each nonlocal N-electron system, Alice first entangles it with the additional electron, and then she projects the additional electron onto an orthogonal basis for dividing the N-electron systems into two groups. In the first group, the N parties obtain a subset of N-electron systems in a maximally entangled state directly. In the second group, they obtain some less-entangled N-electron systems, which are the resource for the entanglement concentration in the next round. By iterating the entanglement concentration process several times, the present ECP has the maximal success probability, which is the theoretical limit of an ECP, equal to the entanglement of the partially entangled state, and higher than the others. This ECP may be useful in quantum computers based on electron-spin systems in the future.

Bao‐Cang Ren, Ming Hua, Tao Li +2 more

We propose a different entanglement concentration protocol (ECP) for nonlocal N -electron systems in a partially entangled Bell-type pure state using the CNOT gates and the projection measurements on an additional electron. For each nonlocal N -electron system, Alice first entangles it with the additional electron, and then she projects the additional electron onto an orthogonal basis for dividing the N -electron systems into two groups. In the first group, the N parties obtain a subset of N -electron systems in a maximally entangled state directly. In the second group, they obtain some less-entangled N -electron systems, which are the resource for the entanglement concentration in the next round. By iterating the entanglement concentration process several times, the present ECP has the maximal success probability, which is the theoretical limit of an ECP, equal to the entanglement of the partially entangled state, and higher than the others. This ECP may be useful in quantum computers based on electron-spin systems in the future.