Why did the theory of quantum computing take so long?

And what is the equivalent low-hanging fruit in your field?

Dwarkesh raises an interesting question in his recent interview with Michael Nielsen. Why did it take so long for quantum computing to develop?

The foundations of quantum computing as a field were only developed in the 1980s. At that point, the basics of classical computation and quantum mechanics had been understood for decades.

So why wasn’t quantum computing developed earlier?

Nielsen’s account is that while the 70s and 80s didn’t have any fundamental theoretical breakthroughs necessary for quantum computing, there was a shift in the salience of the relevant ideas.

Computation became far more salient in the late '70s and early '80s. It just became a thing which many more people were interested in, partially for very banal reasons. You could go and buy a PC. You could buy an Apple II. You could buy a Commodore 64. You could buy all these kinds of things. It became apparent to people that these were very powerful devices, very interesting to think about.

At the same time, in the quantum case, that was also the time of the … ability to trap single ions. Up to that point, we hadn't really had the ability to manipulate single quantum states.

You got these two separate things that for historically contingent reasons had both matured around 1980 or so.

Think about John von Neumann, who died in 1957. If anyone could have invented quantum computing decades earlier, it was him. But he didn’t.

Not because he lacked the knowledge of theory to be able to do so (he was a pioneer in both quantum mechanics and the theory of computation). But because the potential application of quantum mechanical principles to computing wouldn’t have been very obvious. They only became relatively obvious to researchers in the 80s who had seen the decades of progress in computing technology and our control of quantum systems.

If John von Neumann didn’t see the potential of quantum computing in his time, then there are certainly low-hanging ideas in your field that nobody is pursuing.

So much hasn’t been done simply because no one has bothered to do it. The people best positioned to do it might have other priorities for reasons that have nothing to do with the potential fruitfulness of the area of inquiry.

Become the kind of person who can find the low-hanging fruit. Then find it, and do it.