The key experiment/phenomena that sets the basis for photonic quantum computing is the two photon interference experiment.
The physical representation of the information encoding is very easy to understand:
- input: we choose to put or not photons into certain wires or no
- interaction: two wires pass very nearby at some point, and photons travelling on either of them can jump to the other one and interact with the other photons
- output: the probabilities that photos photons will go out through one wire or another
Notable companies pursing it:
- psiQuantum raised 215M in 2020They are very secretive, but we know that they want to reuse classical semiconductor fabrication technologies.Before starting the company, its CEO Jeremy O'Brien was in academia and did actually explain stuff however, see this awesome video: Video 140. "Jeremy O'Brien: "Quantum Technologies" by GoogleTechTalks (2014)".