Quantum randomness

It is usually assumed that even if all else fails a quantum process such as radioactive decay will yield perfect randomness. But in practice the most accurate measurements show phenomena such as 1/f noise, presumably as a result of features of the detector and perhaps of electromagnetic fields associated with decay products. Acceptable randomness has however been obtained at rates of tens of bits per second. Recent attempts have also been made to produce quantum randomness at megahertz rates by detecting paths of single photons. (See also page 1064.)