Decoherence of quantum damped oscillators

Quantum dissipation is studied within two model oscillators, the Caldirola-Kanai (CK) oscillator as an open system with one degree of freedom and the Bateman-Feshbach-Tikochinsky (BFT) oscillator as a closed system with two degrees of freedom. Though these oscillators describe the same classical damped motion, the CK oscillator retains the quantum coherence whereas the damped subsystem of the BFT oscillator exhibits both quantum decoherence and classical correlation. Furthermore, the Amplified subsystem of the BFT oscillator-shows the same degree of quantum decoherence and classical correlation.