Reading About Quantum Computing

For the last several months, I’ve been working on a series of articles about quantum computing: how quantum computers are different from conventional computers, what materials systems might be appropriate for use in qubits, and, for the upcoming last article, how one might actually build and program a quantum computer.

Some of the subtopics are familiar ground for me, and probably for most readers. Patterning niobium superconductors is not that different from patterning aluminum; implanting nitrogen into diamond is fairly similar to implanting dopants into silicon. The technical details vary, but the underlying concepts are familiar.

And then there are quantum algorithms. Understanding computational algorithms is a bit of a stretch for non-computer scientists to begin with, but algorithms for quantum computation introduce a whole other level of strangeness. Understanding them well enough to write about them has been challenging. (Which is why writing this series is taking more time than I might prefer.)

Fortunately, the computer science world has a number of authors who are both able and willing to explain important concepts for non-specialists. People seeking a more detailed discussion of quantum computation could do much worse than these resources.

First, the standard text on the subject, Quantum Computation and Quantum Information, by Nielsen and Chuang. Assumes minimal background in either quantum mechanics or computer science, and only undergraduate level mathematics.

Quantum computers captured the world’s attention in the first place when Shor’s algorithm for factoring large numbers turned out to be much faster than any classical algorithm. Defining quantum speedup when only primitive quantum computers have actually been built is not so easy to do, though. Troels F. Rønnow and colleagues, as part of a collaboration spanning several American and Swiss universities and companies, have done a valuable service in explaining what quantum speedup means, how it might be measured, and how quantum effects can be differentiated from those due to, say, parallelization of the problem.

The papers referenced in the previous paragraph are part of the arXiv.org quantum physics pre-print library. Hosted by the Cornell University Library, arXiv.org is an invaluable source for the latest research in all aspects of physics and related fields. It’s operated and run by and for scientists, and as such must be approached with the understanding that the papers are very technical and often not yet peer-reviewed. Still, it would not be possible to write about leading edge topics without it.

The literature of quantum computing is vast, and I won’t attempt to review it in detail here. After all, the goal of my own articles is to provide an introduction for those who might not have the time or inclination to spend hours reading physics pre-prints. But the resources listed above are a good place to start in understanding why the computer science world finds quantum computing so interesting.