Introduction If you are planning to enter a graduate program in physics in the US, it is fairly certain you will (if you haven't already) hear horror stories about John David Jackson's canonical graduate electrodynamics textbook (simply referred to as "Jackson").

Background In 1967, Carl W. Helstrom (1925-2013) published a paper entitled Minimum mean-squared error of estimates in quantum statistics.

Introduction From the vacuum, different quantum states of light are born.