Heterogeneous Multipartite Entanglement Purification for Size-Constrained Quantum Devices

The problem of distilling Bell pairs in an optimal manner was solved early in the development of the quantum information field, as long as one can assume the availability of perfect local quantum hardware. Much work has since ensued, searching for purification circuits that can approximate this optimum even on realistic noisy hardware, especially in the context of the NISQ era. Multipartite entanglement purification has followed a similar trajectory, including efficient protocols for GHZ and Cluster state purification between distant parties. However, the availability of practical multiparty protocols running on realistic noisy hardware is limited. Here we present a heterogenous approach to entanglement distilation, in which simple small entangled states are directly used as the sacrificial distillation resource in the purification of larger much more expensive entangled resources. Such protocols significantly reduce the network requirements for a NISQ era entanglement distilation.