Quantum Detection and Estimation Theory (Enhanced Edition‪)‬

Information about the world is acquired by observation and measurement,
the results of which are subject to error. One would like to think it could be
eliminated if only one built elaborate enough instruments and took sufficient
pains. All efforts to be free of error will, however, finally reach a bound set by
nature’s underlying chaos, which infects all observations of physical phenomena
with an innate uncertainty. We shall seek out that ultimate limit in a domain
where observations and their inevitable errors can be analyzed with some clarity
and ease, the domain of optics. Although optical astronomy, communications,
and radar furnish our simplest paradigms, the basic concepts to be set forth have
universal applicability.