Light in Quantum Computing and Simulation: Perspective

A summary is given of recent progress in photonic quantum simulation and computation. Non-error-corrected machines performing specialised tasks have already demonstrated a quantum advantage over the best algorithms running on conventional computers, and practical applications for such machines are being explored. Meanwhile, designs for error-corrected fault-tolerant quantum computers based on light are reducing the performance requirements for individual components and systems, although the engineering challenges are severe. Light also plays a central role in other platforms for quantum computing and simulation, from control of individual atomic qubits to remote entanglement of separate processing nodes, along with an important role in communications and other long-distance networks.