Protecting photonic quantum states using topology

The use of topology to protect quantum information is well-known to the condensed-matter community and, indeed, topological quantum computing is a bursting field of research and one of the competing avenues to demonstrate that quantum computers can complete certain problems that classical computers cannot. In photonics, however, we are only beginning to glimpse the potential of topologically-protected photonic quantum states. A handful of experiments have proven signatures of robustness in single photons coupled to topological edge states, and just recently, research has shown that the topology can provide protection to spatial features of biphoton states, and even spatially entangled photonic states. The goal of these pioneering proof-of-principle experiments is to highlight the potential of topology to protect quantum states from disorder and defects, which could change the future landscape in photonic quantum computing