What Makes Quantum Computing So Hard to Explain?

Indeed, developments in the field typically get covered as business or technology stories rather than as science ones.That would be fine if a business or technology reporter could truthfully tell readers, “Look, there’s all this deep quantum stuff under the hood, but all you need to understand is the bottom line: Physicists are on the verge of building faster computers that will revolutionize everything.”The trouble is that quantum computers will not revolutionize everything.Yes, they might someday solve a few specific problems in minutes that (we think) would take longer than the age of the universe on classical computers. They go on to say that a quantum computer would achieve its speed by using qubits to try all possible solutions in superposition—that is, at the same time, or in parallel.This is what I’ve come to think of as the fundamental misstep of quantum computing popularization, the one that leads to all the rest. From here it’s just a short hop to quantum computers quickly solving something like the traveling salesperson problem by trying all possible answers at once—something almost all experts believe they won’t be able to do.The thing is, for a computer to be useful, at some point you need to look at it and read an output. It’s not just a matter of trying all possible answers at once.Compounding the difficulty is that, if you want to talk honestly about quantum computing, then you also need the conceptual vocabulary of theoretical computer science. Understanding this stuff really is possible—after all, it isn’t rocket science; it’s just quantum computing!Original story reprinted with permission from Quanta Magazine, an editorially independent publication of the Simons Foundation whose mission is to enhance public understanding of science by covering research developments and trends in mathematics and the physical and life sciences.WIRED is where tomorrow is realized.