A relay-assisted scheme for quantum key distribution (QKD) over long atmospheric channels is proposed. In this scheme, a polarization orbital-angular-moment with measurement-device-independent (POAM-MDI) QKD for quantum relay is designed to both reconstruct the turbulence-degraded qubits and redirect the qubits to the next relay or to Bob who performs detection randomization. The proposed scheme will neither be time-consuming nor lead to unstable or even intermittent in volatile environments. Theoretical and numerical results show that the proposed relay-assisted scheme outperforms the conventional direct transmission over long atmospheric channels.

中文翻译：

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长大气信道上中继辅助方案的量子密钥分配

提出了一种长大气信道上量子密钥分发（QKD）的中继辅助方案。在此方案中，设计了用于量子中继的具有与测量设备无关（POAM-MDI）QKD 的偏振轨道角矩，以重建湍流退化的量子位并将量子位重定向到下一个中​​继或执行检测的鲍勃随机化。所提出的方案既不会耗时，也不会在不稳定的环境中导致不稳定甚至间歇性。理论和数值结果表明，所提出的中继辅助方案优于长大气信道上的传统直接传输。