How much has quantum computing progressed in the last 5 years?
Re-reading an article from 2020 has a sense of "back to the future"....
I started this substack to discuss what feels like a dizzying rate of progress in quantum technology at the moment. However, coming across this Economist article from September 2020 made me do a double-take. I realise the article is paywalled, but, to summarise, most of the article sounds exactly like it could have been written in September 2025. The main exception is the funding amounts it references - the amounts of money going into funding quantum computing has definitely advanced rapidly in the intervening five years.
In terms of the state of the art, in 2020 it was noted that:
“Some see NISQs as mere stepping stones towards size and stability, and that is certainly the goal of those working on them. A growing number of companies and investors, however, are hopeful that NISQs themselves will be able to do useful work in the meantime. These firms are hunting for “quantum advantage”—a way in which even today’s limited machines might have an impact on their bottom lines, or those of their customers.”
This still true today - today’s quantum computers are still of the NISQ era - noisy, intermediate scale quantum. Most researchers see them as a stepping stone to utility scale quantum computing in the future, but, especially driven by the increase in investment, many are trying to find commercial applications.
However, the status of the search for commercially viable quantum advantage in 2025 is unchanged from what the article stated in 2020:
Finding algorithms that are both commercially useful and simple enough to work within a NISQ machine’s limitations is not easy. A report […] reminded readers that no commercial applications are currently known to exist.
Of course, some organisations are still chasing headlines of claiming quantum advantage. In 2020:
“The industry [was] cheered by Google’s demonstration last year of “quantum supremacy”, in which it used a NISQ machine to perform, with minutes of computing time, a calculation that would have taken thousands of years on classical hardware. Google’s calculation was highly contrived and of little use in the real world.”
Five years later, we fondly recall last year’s announcement by Google of how they used their quantum Willow chip to perform a calculation in under five minutes that would apparently take a supercomputer 10 septillion years. Of course, the calculation was still for an example (RCS sampling) that is contrived and of no practical interest for any real-world application.
Meanwhile, some of the main players in developing qubit hardware are progressing. In 2020,
“Microsoft [… was] working on a “topological” quantum computer that relies on the interactions of super-cold electrons”.
As Microsoft announced in 2025, they might have created one such qubit, or maybe they haven’t.
Also in 2020,
“One particularly well-financed new firm is PsiQuantum, which does its computing with photons that run along waveguides etched onto ordinary silicon chips. It hopes to leapfrog the NISQ era entirely and produce a fully fledged quantum computer within about five years.”
By 2025 PsiQuantum are even better financed, thanks to $1bn from the Australian Government in 2024, and a further $1bn financing round this year, on the basis of a plan to build a large scale fault tolerant quantum computer using photons. This is due to be completed by 2030, which would be (checks notes….) within about five years.
I know there have been some real advances in the technology over the last five years, and even though I’d put myself in the sceptic/realist class, I do believe we are closer to utility scale quantum computing in 2025 than we were in 2020. An optimistic point of view is that maybe the hype levels were (relative to reality) even higher in 2020 than now, and reality has caught up to an extent? Either way, plenty of food for thought….