  Quantum entanglement, a key resource in quantum information processing, is
reduced by interaction between the quantum system concerned and its unavoidable
noisy environment. Therefore it is of particular importance to study the
dynamical properties of entanglement in open quantum systems. In this work, we
mainly focus on two qubits coupled to an adjustable environment, namely a
semi-infinite transmission line. The two qubits' relaxations, through
individual channels or collective channel or both, can be adjusted by the
qubits' transition frequencies. We examine entanglement dynamics in this model
system with initial Werner state, and show that the phenomena of entanglement
sudden death and revival can be observed. Due to the hardness of preparing the
Werner state experimentally, we introduce a new type of entangled state called
pseudo-Werner state, which preserves as much entangling property as the Werner
state, and more importantly, is experiment friendly. Furthermore, we provide
detailed procedures for generating pseudo-Werner state and studying
entanglement dynamics with it, which can be straightforwardly implemented in a
superconducting waveguide quantum electrodynamics system.
