Optical Cluster States Could Enable One-Way Quantum Computing

Using a compact optical platform, a research team at Institut National De La Recherche Scientifique (INRS) has generated a high-dimensional, d-level cluster state and has used it to perform quantum computing operations. According to the researchers, the platform they have developed is capable of generating quantum states with complexities sufficient to achieve one-way quantum computing objectives.

By judiciously designing the quantum state of photons, it is possible to increase the information storage capacity of qubits to obtain the so-called qudits used by the researchers. By grouping the qudits into clusters, the researchers achieved high-dimensional, one-way quantum computing operations, where processing was performed through measurements.

The INRS team, led by professor Roberto Morandotti, characterized and tested the noise sensitivity of 3-level, 4-partite cluster states formed by two photons in the time and frequency domain. The researchers confirmed genuine multipartite entanglement with higher noise robustness compared to conventional 2-level cluster states. They performed proof-of-concept high-dimensional one-way quantum operations, where the cluster states were transformed into orthogonal, maximally entangled d-level 2-partite states by means of projection measurements.

Professor José Azaña said photons present an advantage over other approaches to quantum processing: “They are used to transmit information via optical fibers in existing telecommunications systems. That means photons with controlled quantum properties can also travel through these same channels without losing their attributes.”

The team’s scalable approach is based on integrated photonic chips and optical fiber communication components. The compact system is made from commercially available components and is compatible with existing electronics and telecommunications technologies. The generation of cluster states based on subsystems that have more than two dimensions, that is, d-level cluster states, could increase quantum resources and also enable novel algorithms.

The research was published in Nature Physics (doi: https://doi.org/10.1038/s41567-018-0347-x).