title: Long-range Cooper pair splitter with high entanglement production rate.
abstract: Cooper pairs in the superconductor are a natural source of spin entanglement. The existing proposals of the Cooper pair splitter can only realize a low efficiency of entanglement production, and its size is constrained by the superconducting coherence length. Here we show that a long-range Cooper pair splitter can be implemented in a normal metal-superconductor-normal metal (NSN) junction by driving a supercurrent in the S. The supercurrent results in a band gap modification of the S, which significantly enhances the crossed Andreev reflection (CAR) of the NSN junction and simultaneously quenches its elastic cotunneling. Therefore, a high entanglement production rate close to its saturation value can be achieved by the inverse CAR. Interestingly, in addition to the conventional entangled electron states between opposite energy levels, novel entangled states with equal energy can also be induced in our proposal.
authors.affiliation: College of Science, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Chen
authors.affiliation: College of Science, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China.
authors.forename: D N
authors.initials: DN
authors.lastname: Shi
authors.affiliation: 1] National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093, China [2] Collaborative Innovation Center of Advanced Microstructures.
authors.forename: D Y
authors.initials: DY
authors.lastname: Xing