Design of a Quantum-Repeater using Quantum-Circuits and benchmarking its
  performance on an IBM Quantum-Computer
Quantum communication relies on the existence of entanglement between two
nodes of a network. However, due to its fragile nature, it is nearly impossible
to establish entanglement at large distances through the direct transmission of
qubits. Quantum repeaters have been proposed to solve this problem, which
split-up the network to create small-scale entangled links and then connect
them up to create the large-scale link. As researchers race to establish
entanglement over larger and larger distances, it becomes essential to gauge
the performance and robustness of the different protocols that have been
proposed to design a quantum repeater, before deploying them in real life.
Currently available noisy quantum computers are ideal for this task, as they
can emulate the noisy environment in a quantum communication channel, and
provide a measure for how the protocols will perform on real-life hardware. In
this paper, we report the circuit-level implementation of the complete
architecture of a quantum repeater, and benchmark this protocol on IBM's cloud
quantum computer - IBMQ. Our experiments indicate a 26% fidelity of shared
bell-pairs for a complete on-chip quantum repeater with a yield of 49%. We also
compare these results with simulation data from IBM Qiskit. The results of our
experiments provide a quantitative measure for the fidelity of entanglement
that currently available repeaters can establish. In addition, the proposed
circuit-implementation provides a robust benchmark for state-of-the-art quantum
computing hardware.
Sowmitra Das Md. Saifur Rahman Mahbub Majumdar