Scaled quantum theory. The bouncing ball problem

TL;DR

This paper explores scaled quantum theory applied to the bouncing ball problem, demonstrating a smooth quantum-classical transition through a continuous parameter in a unified framework.

Contribution

It introduces a linear scaled von Neumann equation for mixed states and shows how it describes the gradual quantum-classical transition in conservative systems.

Findings

Quantum features fade gradually towards classical behavior.

The transition is governed by a continuous parameter.

Unified description of quantum and classical regimes.

Abstract

Within the so-called scaled quantum theory, the standard bouncing ball problem is analyzed under the presence of a gravitational field and harmonic potential. In this framework, the quantum-classical transition of the density matrix is described by the linear scaled von Neumann equation for mixed states and after it has been particularized to the case of pure states. The main purpose of this work is to show how this theory works for conservative systems and the quantum-classical transition is carried out in a continuous and smooth way, being equivalent to a nonlinear differential wave equation which contains a transition parameter ranging continuously from one to zero and covering all dynamical regimes in-between the two extreme quantum and classical regimes. This parameter can be seen as a degree of quantumness where all intermediate dynamical regimes show quantum features but are fading gradually when approaching to the classical value.