Dynamical Processes in Exactly Solvable Quantum Mechanical Systems: III
Sachiko Kitajima, Fumiaki Shibata · Journal of the Physical Society of Japan · 2001
Entropy dynamics of the Coleman–Hepp and the boson detector models are solved by calculating the von Neumann entropy exactly. This is done with the use of our previous results of the density matrices and newly obtained entropy formulae. Randomization and recoherence are found for spin entropy of an incident particle of the CH model when an interaction is strong whereas a staircase increase is observed for the weaker interaction. For the boson detector model, a monotonous time evolution of the entropy is found for arbitrary strength of interaction. Entropy dynamics for detector systems are also determined. Response of the detector depends on the interaction strength, magnitude of detector spins and number of constituent elements of the detectors. Reciprocity relation of entropy between an incident particle and a constituent detector element is found.