Decoherence of Coupled Oscillators and Qubits

We study the dynamics of open systems of coupled oscillators and qubits in minimal environments. To determine the decoherence of the system, we calculate the linear entropy for various initial states and visualize the dynamics with Husimi functions and Bloch spheres. Increasing the interaction of the system with its environment results in more rapid decoherence. For coupled oscillators under the rotating wave approximation we find periodic linear entropies whereas for the anti-rotating wave approximation the linear entropy can lose periodicity. For a qubit system coupled to an oscillator environment we find oscillatory linear entropies that are pseudo-periodic.