Abstract
Maximally bipartite entangled state , also known as the Einstein-Podolsky-Rosen pair, is the unit resource of entanglement and the key for quantum information processing. An important problem is that how many maximally bipartite entangled states could be distilled from a multipartite entangled state shared among a quantum network. Here, we focus on the distillation of from a single copy of the three-qubit state. An interesting phenomenon in this case is that the random entanglement distillation between two unspecified parties can yield a strictly higher distillation rate (the average number of distilled from each state) than the case between two specified parties. In this work, we develop a distillation protocol by introducing weak measurements that do not destroy the global entanglement. We find that the distillation rate can be significantly enhanced with only a few rounds by performing an extra distillation procedure between two specified parties at the final step. Experimentally, we prepare a three-photon state in the polarization degree of freedom, and employ the path degree of freedom of each photon as probe qubits to realize the weak measurement. As a proof-of-principle demonstration, we show that the distillation rate is enhanced from , which is the theoretical limit of any distillation scheme between two specified parties, to between two unspecified parties with only one distillation round.
- Received 1 April 2019
- Revised 23 January 2020
- Accepted 20 March 2020
DOI:https://doi.org/10.1103/PhysRevResearch.2.023047
Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.
Published by the American Physical Society