Entanglement purification and concentration based on hybrid spin entangled states of separate nitrogen-vacancy centers

¹ School of Science, Beijing University of Posts and Telecommunications - Beijing, 100876, China
² State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications - Beijing, 100876, China

Received: 23 March 2019
Accepted: 30 May 2019

Abstract

We present a hybrid entanglement purification and concentration protocol for nuclear spin entangled states of nitrogen-vacancy (N-V) centers resorting to the ancillary photons and electrons. In the entanglement purification protocol, the mixed entangled states of the N-V centers can be purified with high fidelity using two pairs of entangled photons to interact with each electron in N-V centers. By performing local measurement on the electrons, the original entangled state can be obtained between the two remote parities. In the entanglement concentration protocol, the partially entangled states of the nuclear spin in N-V centers can be concentrated to the maximally entangled state by using an ancillary photon on one local user. The fidelity of the entangled state with different excited state decay rate and the relation between the yield and different decay rate are numerically simulated.