Misbelief and misunderstandings on the non--Markovian dynamics of a damped harmonic oscillator

Abstract

We use the exact solution for the damped harmonic oscillator to discuss some relevant aspects of its open dynamics often mislead or misunderstood. We compare two different approximations both referred to as Rotating Wave Approximation. Using a specific example, we clarify some issues related to non--Markovian dynamics, non--Lindblad type dynamics, and positivity of the density matrix.

6 pages, 2 figures, added info: submitted to J. Opt. B: Quantum and Semiclass. Opt., Special Issue of the 10th Central European Workshop on Quantum Optics, reference added, discussion clarified