Phase-space functions: can they give a different view of quantum mechanics?

Y S Kim, Marilyn E. Noz

Kedar S. Ranade

The concept of quantum phase space offers a view on quantum mechanics, which is different from the standard Hilbert space approach, but which more closely resembles the classical phase space. Due to the properties of quantum mechanics there are several equivalent quantum phase space descriptions, and one cannot always prefer one or another as they all have certain merits and drawbacks. For example, the Husimi-Kano Q function is a probability distribution and thus gives rise to entropic quantities, namely the Renyi-Wehrl entropies, of which several properties are known. The Wigner function, on the other hand, has an easier physical explanation, but may take negative values. In this article, we investigate entropic measures of localisation for a state in quantum phase space by using the Beckner-Brascamp-Lieb inequality to relate different phase-space functions.

Gabino Torres-Vega

Classical and Quantum Mechanics make use of different objects and they also were written on different background spaces.As a consequence, they have followed different paths regarding the mathematical objects that they use.Classical Mechanics makes use of points and functions on a real cotangent space T * Q of a mechanical system, and makes use of differential geometry as the basic language with which the theory is developed.This is due to the existence of trajectories of single points.On the other side, Quantum Mechanics makes use of state vectors in a complex Hilbert space, with operators, commutators, and eigenvectors, and makes use of some postulates that look weird from a classical point of view.This is a point of view that was induced by the lack of trajectories and by the use of probabilistic interpretations of state vectors.There have been efforts to define similar classical and quantum functions that can be compared with each other.Quantum densities were written as functions on phase-space by means of integral transformations.Two of these transformations are the Wigner (

Nicolaas P. Landsman

Franklin E. Schroeck

Maciej Przanowski, Jaromir Tosiek, Francisco J. Turrubiates

Abstract Classical model of light in helicity formalism is presented. Then quantum mechanical point of view at photons – construction and interpretation of two equivalent photon wave functions are proposed. Quantum mechanics of photon is investigated. The Białynicki – Birula scalar product and the generalized Hermitian conjugation of linear operator are discussed. Quantum description of light on a phase space based on the Weyl – Wigner – Moyal approach is developed. A photon Wigner function is built. Some explicit photon Wigner functions for different kernels are obtained.