  An array of ultracold polar molecules trapped in an external electric field
is regarded as a promising carrier of quantum information. Under the action of
this field, molecules are compelled to undergo pendular oscillations by the
Stark effect. Particular attention has been paid to the influence of intrinsic
decoherence on the model of linear polar molecular pendular states, thereby we
evaluate the tripartite entanglement with negativity, as well as fidelity of
bipartite quantum systems for input and output signals using electric dipole
moments of polar molecules as qubits. According to this study, we consider
three typical initial states for both systems respectively, and investigate the
temporal evolution with variable values of the external field intensity, the
intrinsic decoherence factor and the dipole-dipole interaction. Thus we
demonstrate the sound selection of these three main parameters to obtain the
best entanglement degree and fidelity.

Quantum Physics