Fig. 7: Comparing hardware costs between one- and two-way quantum repeaters.
From: Comparing one- and two-way quantum repeater architectures
Number of a repeaters, and b qubits required per burst for each unit secret-key delivered for optimal performance for one- and two-way repeater architectures. The red dashed line shows the number of repeaters required for the optimal Quantum Parity Code (QPC), the blue dotted line shows the number of repeaters required for optimal performance for 2G-NC, the black and the gray solid lines are the envelopes for the number of repeaters required for the optimal performing multiplexed two-way schemes (MTP) using a Fth = 0.95 and a SKR-based distillation decision rule respectively. To note, we do not consider the ancilla qubits required for state preparation or teleportation-based error correction for QPC, and the estimation presented here is a lower bound. For all long-distance parameter regimes considered, the MTP requires significantly less number of repeaters and qubits than the QPC. Compared to the 2G-NC, the MTP (SKR rule) scheme requires a similar number of repeaters but less number of qubits for delivering a unit secret-key. To note, MTP using the Fth rule requires slightly more repeaters than the MTP based on the SKR rule, and the 2G-NC protocol, but a lower number of repeaters than the QPC.
