Controllable entanglement transfer via two parallel spin chains

Transferring quantum states between nearby quantum processors is important for building up a powerful quantum computer. In this paper, we propose a controllable scheme to transfer bipartite entangled states using two open-ended spin-1/2 chains in parallel as a dual-rail quantum channel. We perform two sets of operations, one on one end of the chains at the beginning of the system evolution and the other on the other end of the chains at the time the transferred entanglement needs to be picked up. Among the operations employed in the scheme there are weak measurements with controllable strengths. By suitably choosing the strengths of these weak measurements, the entanglement transferability is pronouncedly improved, compared to that due to the spin chains' natural dynamics. In principle, the entanglement amount at the receiving site can be made arbitrarily close to that at the sending site, i.e., perfect entanglement transfer could be achieved asymptotically. - Highlights: • Entanglement transfer between short-distance micro-processors is studied. • Open-ended spin-1/2 chains connecting the processors serve as the quantum channel. • Entanglement transferability is enhanced by weak measurements at the chains' ends. • Perfect entanglement transfer could be achieved asymptotically