Two coupled qubits under the influence of a minimal, phase-sensitive environment

Abstract

In this work, we investigate the influence of a minimal, phase-sensitive environment on a system of two coupled qubits. The environment is constituted by a single-mode field initially prepared in a type of Schr\"odinger cat state, a quantum superposition of two squeezed coherent states. We present an analytical solution to the model and investigate the degradation of the quantum features of the system due to the action of the environment. In particular, we find that the time-averaged linear entropy for long times, $\bar{S}_T$, has approximately a linear dependence on Mandel's $Q$ parameter as well as on the variance of the $\hat{X}$ quadrature of the initial state of the environment.