Teleportation is a fundamental concept of quantum mechanics with an important application in extending the range of quantum communication channels via quantum relay nodes. To be compatible with real-world technology such as secure quantum key distribution over fibre networks, such a relay node should ideally operate at GHz clock rates and accept time-bin encoded qubits in the low-loss telecom band around 1550 nm. Here, we show that InAs/InP droplet epitaxy quantum dots with their sub-Poissonian emission near 1550 nm are ideally suited for the realisation of this technology. To create the necessary on-demand photon emission at GHz clock rates, we develop a flexible pulsed optical excitation scheme, and demonstrate that the fast driving conditions are compatible with a low multiphoton emission rate. We show further that, even under these driving conditions, photon pairs obtained from the biexciton cascade show an entanglement fidelity close to 90%, comparable to the value obtained under cw excitation. Using asymetric Mach Zehnder interferometers and our photon source, we finally construct a time-bin qubit quantum relay able to receive and send time-bin encoded photons, and demonstrate mean teleportation fidelities of $0.82\pm 0.01$, exceeding the classical limit by more than 10 standard deviations.

中文翻译：

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千兆赫时钟在时域量子位的隐形传态

隐形传态是量子力学的基本概念，在通过量子中继节点扩展量子通信通道范围方面具有重要应用。为了与现实世界的技术（例如通过光纤网络安全地分配量子密钥）兼容，这种中继节点理想上应以GHz时钟速率运行，并在1550 nm左右的低损耗电信频段中接受时间段编码的量子比特。在这里，我们显示InAs / InP液滴外延量子点及其1530 nm附近的次泊松发射非常适合实现该技术。为了在GHz时钟速率下创建必要的按需光子发射，我们开发了一种灵活的脉冲光激发方案，并证明了快速驱动条件与低多光子发射率兼容。我们进一步证明，即使在这些驱动条件下，从双激子级联获得的光子对也显示出接近90％的纠缠保真度，与在cw激发下获得的值相当。最后，我们使用非对称Mach Zehnder干涉仪和我们的光子源，构建了一个能够接收和发送时分编码光子的时分量子位量子继电器，并证明了平均时空传输保真度。$0.82\pm 0.01$，超出经典限制的标准偏差超过10个。