Generalized Anti-Wick Quantum States

Abstract

The purpose of this Note is to study a simple class of mixed states and the corresponding density operators (matrices). These operators, which we call quite Toeplitz density operators correspond to states obtained from a fixed function ("window") by position-momentum translations, and reduce in the simplest case to the anti-Wick operators considered long ago by Berezin. The rigorous study of Toeplitz operators requires the use of classes of functional spaces defined by Feichtinger.