[gregfjohnson]

I became curious about quantum computing a few years ago. Googling around, I came across the QC chapter in Dasgupta. I found their description of the topic to be excellent, exactly what I was searching for. They provide a substantive presentation of QC, as contrasted with many "pop sci" hand-wavy impressionistic descriptions of QC. They tactfully avoid a few of the extremely difficult proofs, but they do give a solid mathematical underpinning for the subject. And, they convey in prose what the point of the whole thing is. Also, they forthrightly express the mysterious nature of what seems to be going on here. (If you have an N-qubit quantum computer, the universe seems to somehow maintain and manipulate a vector of 2^N complex elements as a quantum computation proceeds.)

They give a brilliant presentation of Shor's factorization algorithm, and how quantum computers offer an amazingly natural way to do FFT's (a key aspect of the Shor algorithm).

I would not contest the OP's questioning of the choice of a chapter on QC in an undergrad algorithms textbook. I would, however, offer the standard "your mileage may vary" caveat to the OP's very negative characterization. I had no idea what QC was about, and this chapter provided me with a great "on-ramp" to understanding what QC is all about.