Quantum computers have been a buzzword that’s lasted for 40 years. While research papers get pumped out in epic proportions, the fundamentals of quantum computing remain fundamentally broken.

The Case Against Quantum Computing was written 5 years ago now, a time when everyone’s mind was melting about quantum computing, and every major point of the article is still valid.

I recommend the whole article, but if I had to pick an excerpt sentence, it would be this:

The number of qubits used for them is below 10, usually from 3 to 5. Apparently, going from 5 qubits to 50 (the goal set by the ARDA Experts Panel for the year 2012) presents experimental difficulties that are hard to overcome. Most probably they are related to the simple fact that 25 = 32, while 250 = 1,125,899,906,842,624.

Despite much of the Quantum research community condemning the article when it came out, meaningful progress is nowhere to be seen. Per a Nature article in 2023: “Quantum computers: what are they good for? For now, absolutely nothing. But researchers and firms are optimistic about the applications.” - But there’s more fun facts:

This is where the scepticism about quantum computing begins. The world’s largest quantum computer in terms of qubits is IBM’s Osprey, which has 433. But even with 2 million qubits, some quantum chemistry calculations might take a century, according to a 2022 preprint2 by researchers at Microsoft Quantum in Redmond, Washington, and ETH Zurich in Switzerland. Research published in 2021 by scientists Craig Gidney at Google in Santa Barbara, California, and Martin Ekerå at the KTH Royal Institute of Technology in Stockholm, estimates that breaking state-of-the-art cryptography in 8 hours would require 20 million qubits.