Quantum communication is a secure way to transfer quantum information and tocommunicate legitimate parties over the distant places in a network. Althoughcommunication over a long distance has already been attained, technical problemarises due to unavoidable loss of information through the transmission channel.Briegel, D"{u}r, Cirac and Zoller (BDCZ) developed the concept of quantumrepeaters which could extend the distance scale using entanglement swapping andquantum memory. Entanglement swapping has been realized experimentally usingentangling photons. Recently, quantum repeater has been demonstrated. However,it has remained a challenging problem to implement a quantum memory. Here wedemonstrate entanglement swapping for two pair of superconducting qubits whichis an essential part of a repeater. A quantum computer can then be used tostore and retrieve the information by introducing an ancilla which could bethought of as a quantum memory. Here we use IBM's real quantum processor namedibmqx4 to create two pair of entangled qubits, then we design an equivalentquantum circuit which consequently swaps the entanglement between two pairs.The information is then stored in the qubits which can be retrieved by themeans of an ancilla, eventually the whole system acting as a quantum repeaterintegrating the concept of both entanglement swapping and quantum memory.
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