Entanglement and its role on the capacity of noisy two-Pauli channels

摘要

The discovery of super dense coding paved the way for future quantum communications that exploit the power of entanglement. The protocol lets users communicate two classical bits using a pre-shared entangled pair of qubits called a Bell pair. However, the protocol assumes that a noiseless channel exists between end users. Moreover, perfect Bell pairs may not always be created in any experimental set up. We study the single shot communication properties of partially entangled Werner state and partially entangled pure bipartite states by considering the two-Pauli channel. The two-Pauli channel accommodates for both bit flips and phase flips that qubits may suffer during transmission. Quantification of entanglement is done via entanglement of formation and its dependence on capacity is analyzed.