Wick Calculus
  In quantum field theory, physicists routinely use "normal ordering" of operators, which just amounts to shuffling all creation operators to the left. Potentially confusing, then, is the occurrence in the literature of normal-ordered functions, sometimes called "Wick transforms". We aim to introduce the reader to some basic results and ideas around this theme, if not the mathematical subtleties; our intended audience are instructors who want to add something to their quantum field theory course, or researchers who are interested but not specialists in mathematical physics. For rigorous proofs and careful mathematical discussions we only give references. 
Alexander Wurm, Marcus Berg