Classical and Quantum Descriptions

Yu. A. Rylov

It is shown that the number of dynamical variables (computer storage) which is necessary for a description is similar for the coupled quantum-classical description and for the pure quantum one. In the Schrödinger representation, the dynamic equations of the coupled quantum-classical description are shown to be nonlinear in terms of the wave function and incompatible with the quantum axiomatics. As a result, the quantum-classical description appears to be impossible in the Heisenberg representation, because it uses essentially the quantum axiomatics, which is incompatible with the quantum-classical description. An idea of a description, intermediate between the purely quantum description and the classical one, is suggested. In this case, the number of dynamic variables (computer storage) is several times as large as the classical description, but it is much less than at the pure quantum description. ©1999 John Wiley & Sons, Inc. Int J Quant Chem 72: 483–498, 1999

A.G. Sitenko

Hans Albrecht Bethe

It is of interest to exhibit the relationship between the quantum mechanical and classical descriptions of the elastic scattering process, and investigate the conditions under which the two descriptions are equivalent. We begin with the classical description.

Bob Coecke, Bart D’Hooghe, Frank Valckenborgh

Simon Friederich

One of the defining aspects of the epistemic conception of quantum states is that it conceives of quantum states as non-descriptive. In this section, I consider the criticism that any non-descriptive reading of quantum states entails an unattractive ontological quantum/classical divide. This divide is supposed to separate a realm of classical macro-objects, which are susceptible to descriptions in terms of classical concepts, from a realm of quantum micro-objects, for which no descriptive account can be given at all.