Photons make robust quantum-information carriers because they don’t directly interact with each other. The price for this is that getting them to interact on demand for the purpose of computation is a challenge. Led by Dr Nicolas Menicucci, the Deterministic Entanglement Work Package will explore two approaches to overcoming this challenge: (1) implementing a deterministic two-photon entangling gate using a quantum memory; and (2) demonstrating continuous-variable (CV) entanglement with squeezing above the threshold required for fault-tolerant quantum computation.
A two-photon entangling gate is required in a photonic-qubit-based computation, while CV methods offer a top-down approach in which all required entanglement is imparted into a cluster state in one shot at the beginning, after which measurements implement the computation. Both are promising technologies, and they share much of the same underlying technology.