Abstract:

The Kraus operator-sum representation method for mixed-state evolution was used to analyze the change in the fidelity and von Neumann entropy of the final state after decoherent time evolution. The analysis was based on the Jaynes-Cummings model for the initial state set in the depolarization mode. The results show that the fidelity of the quantum state undergoing decoherent evolution exhibits decaying oscillations with time until it becomes stable, while the von Neumann entropy exhibits oscillations of decreasing amplitude with time.

Key words: decoherence, Jaynes-Cummings model, Kraus operator-sum representation, fidelity, von Neumann entropy