Reducing quantum control for spin-spin entanglement distribution

Abstract

We present a protocol that sets maximum stationary entanglement between remote spins through scattering of mobile mediators without initialization, post-selection or feedback of the mediators' state. No timeresolved tuning is needed and, counterintuitively, the protocol generates twoqubit singlet states even when classical mediators are used. The mechanism responsible for this effect is resilient against non-optimal coupling strengths and dephasing affecting the spins. The scheme uses itinerant particles and scattering centres and can be implemented in various settings. When quantum dots and photons are used a striking result is found: injection of classical mediators, rather than quantum ones, improves the scheme efficiency. © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft.