A commenter on my last post — who, since he or she chose not to provide a name, I’ll take the liberty of calling Dr. Doofus McRoofus — offers the following prediction about quantum computing:
[U]nless quantum computing can deliver something practical within the next five to ten years it will be as popular then as, say, PRAMs are today.
- String theory has been immensely popular for over 20 years, among a much larger community, with zero prospects for delivering anything practical (or even any contact with experiment, which — ahem — some of us have had for a decade). Reasoning by analogy, if quantum computing became popular around 1995, that should at least put us in the upper range of McRoofus’s “five to ten years.”
- For better or worse, the funding outlook for quantum computing is much less depressing right now than for classical theoretical computer science. Many of us have been making the case to DARPA and NSF that classical complexity should continue to be funded in part because of its relevance for quantum computing.
- The right analogy is not between quantum computing and PRAM’s; it’s between quantum computing and parallel computing. Specific architectures, like linear optics and PRAM’s, have gone in and out of fashion. Modes of computation, like nondeterminism, randomness, parallelism, and quantumness, have instead just gotten agglomerated onto the giant rolling snowball of complexity. As long as the snowball itself continues to tumble down the hill (shoot — bad metaphor?), I don’t see any reason for this to change.
- I’m no good at predicting social trends, so perhaps time will prove me wrong and Dr. McRoofus right. But speaking for myself, I’d go insane if I had to pick research topics based on popularity. I became interested in quantum computing because of a simple trilemma: either (i) the Extended Church-Turing Thesis is false, (ii) quantum mechanics is false, or (iii) factoring is in classical polynomial time. As I put it in my dissertation, all three possibilities seem like wild, crackpot speculations, but at least one of them is true! The question of which will remain until it’s answered.