Can quantum discord increase in a quantum communication task?

Abstract

Quantum teleportation of an unknown quantum state is one of the few communication tasks which has no classical counterpart. Usually the aim of teleportation is to send an unknown quantum state to a receiver. But is it possible in some way that the receiver's state has more quantum discord than the sender's state? We look at a scenario where Alice and Bob share a pure quantum state and Alice has an unknown quantum state. She performs joint measurement on her qubits and channel to prepare Bob's qubits in a mixed state which has higher quantum discord than hers. We also observe an interesting feature in this scenario, when the quantum discord of Alice's qubits increases, then the quantum discord of Bob's prepared qubits decreases. Furthermore, we show that the fidelity of one-qubit quantum teleportation using Bob's prepared qubits as the channel is higher than using Alice's qubits.