Cluster states are a particularly important class of multi-partite states, formed by multiple parties, such as multiple atoms or photons, characterized by two unique properties: maximal connectedness and highest persistency of entanglement. These properties make cluster states equivalent to universal one-way quantum computers, where different algorithms can be implemented by performing measurements on the individual parties of the cluster states. This approach greatly simplifies quantum processing. In this work, we present a general approach to prepare and coherently manipulate discrete d-level multi-partite quantum systems based on the simultaneous entanglement, or hyper-entanglement, of two photons in time and frequency, by exploiting integrated photonics circuits. This is the first experimental realization and characterization of qudit cluster states as well as the first hyper-entangled state employing only a single degree of freedom.
Read more at Nature Physics: https://www.nature.com/articles/s41567-018-0347-x
03 Dec 2018