i will need to actually watch the video to see what this means. because there have been machines that can compute things quantum mechanically for quite a while, such as DWAVE (which does simulated annealing, quite useful for things like Hamiltonian paths but not a universal computer) and lab instantiations of quantum walks, which are universal for quantum computation but the lab instantiations to my knowledge are not. plus the optical quantum computers that have been around for a long time. all of these can be abstracted as circuits.integrated circuit is obviously something quite different.
the issue with quantum computers is less that we can't build one and more that we can't scale them. in fact when i was working in this area (2013.... so i'm sure i'm massively out of date) we didn't even have a proof that quantum mechanical systems could be made to do scalable computation. we also didn't know where BQP (bounded error quantum polynomial time) lay with respect to NP (non deterministic polynomial time), or NP to P (polynomial time), i.e. whether our algorithms are just shit or there is some fundamental difference in complexity between these classes. so it wasn't even clear whether quantum computers even gave us any advantage.
anyway, i will watch this when i'm not about to go to bed. i really hope this is as exciting as the headline suggests.
ps the reason quantum computing would revolutionanise medicine is because certain important problems, such as whether a drug would bind to a receptor, are inherently quantum mechanical, because all chemistry is really. anything that required molecular simulation is hobbled on a classical computer, if you want to simulate something like DNA, right now you're pretty much left with ball and stick models. quantum computing would enable us to represent the inherently quantum mechanical nature of matter. similarly for energy, light harvesting bacteria require quantum mechanical transport to be able to efficiently transport incident energy to the places where that energy can be used. if they don't do that, the energy damages the rest of the cell. so quantum mechanical understanding of materials science would help us get better at shit like building solar panels that aren't shiny.
