Quantum Computing – Hype vs. Reality

TLDR; Be pessimistic, and let reputable sources such as Scott Aaronson’s blog inform you about the real progress being made.

With recent developments in quantum computing, as well as a surge of media around the progress and use of this technology, it can be difficult to determine exactly what is hype and what is reality. Most of the discussion is around the idea of quantum supremacy – the point at which we can perform a specific type of computation on a quantum computer much faster than on a classical computer.

What makes this discussion difficult? For one, the choice of problem / computation to evaluate on a given quantum computer versus a classical one is entirely up to the researcher. In other words, the problem doesn’t need to be a “useful” one – any problem that exhibits that the QC can perform better than the classical computer will do.

Second, the evaluation is very hardware dependent. As Aaronson summarizes in his blog post, a group that aims to show quantum supremacy can say “oh look, we computed this result on our QC which would take a million years on a large classical computer.” However, by creating better classical algorithms, or using larger machines, another group can say “your QC on this problem is not that great.”

Why is there this discussion in the first place, isn’t it obvious that quantum computers are better than classical computers? Not quite – at the time of writing, it has not been proven (in a theoretical sense) that QCs are actually any better than classical computers. In fact, a common theme we see is that breakthroughs in QC algorithms lead to improvements in classical algorithms, which sometimes even beat their quantum counterparts.

If I were you, I would remain pessimistic when seeing titles such as “Quantum Computer Solves Impossible Problem.” Just stick with the facts – yes, quantum computers exist, and yes there are some quantum algorithms that are better than their known classical counterparts, but these QC companies will claim tons of progress, and it’s best to see what the experts say.

P.S. I would definitely take a look at the Quantum Bullshit Detector – I have no idea who runs this account, but their classifications seem very plausible.