Continuous Variable Entanglement of Two Mesoscopic Josephson Junctions Induced by a Thermal Radiation Field

The continuous-variable(CV) entanglement between two mesoscopic Josephson junctions isstudied and the time-dependent characteristic function in Wignerrepresentation for the Josephson junction subsystem driven by asingle-mode thermal field is analytically obtained. It is found thatan initial lowest energy state of the junction subsystem can evolveinto a two-mode entangled Gaussian state through the interactionwith the thermal radiation field. Furthermore, we investigate theinfluence of the temperature on the entanglement of the junctionsand find that the CV entanglement of the two junctions shows thecritical behavior with respect to the temperature.