Owing to the inevitable loss in communication channels, the distance of entanglement distribution is limited to approximately 100 kilometres on the ground¹. Quantum repeaters can circumvent this problem by using quantum memory and entanglement swapping². As the elementary link of a quantum repeater, the heralded distribution of two-party entanglement between two remote nodes has only been realized with built-in-type quantum memories^{3,4,5,6,7,8,9}. These schemes suffer from the trade-off between multiplexing capacity and deterministic properties and hence hinder the development of efficient quantum repeaters. Quantum repeaters based on absorptive quantum memories can overcome such limitations because they separate the quantum memories and the quantum light sources. Here we present an experimental demonstration of heralded entanglement between absorptive quantum memories. We build two nodes separated by 3.5 metres, each containing a polarization-entangled photon-pair source and a solid-state quantum memory with bandwidth up to 1 gigahertz. A joint Bell-state measurement in the middle station heralds the successful distribution of maximally entangled states between the two quantum memories with a fidelity of 80.4 ± 2.2 per cent (±1 standard deviation). The quantum nodes and channels demonstrated here can serve as an elementary link of a quantum repeater. Moreover, the wideband absorptive quantum memories used in the nodes are compatible with deterministic entanglement sources and can simultaneously support multiplexing, which paves the way for the construction of practical solid-state quantum repeaters and high-speed quantum networks.

由于通信信道不可避免的损失，纠缠分布的距离在地面上被限制在大约 100 公里¹。^{量子中继器可以通过使用量子存储器和纠缠交换2}来规避这个问题。作为量子中继器的基本链路，预示着两个远程节点之间两方纠缠的分布只有内置式量子存储器才能实现^{3,4,5,6,7,8,9}. 这些方案受到多路复用容量和确定性属性之间的权衡的影响，因此阻碍了高效量子中继器的开发。基于吸收式量子存储器的量子中继器可以克服这些限制，因为它们将量子存储器和量子光源分开。在这里，我们展示了吸收性量子存储器之间预示纠缠的实验演示。我们构建了两个相距 3.5 米的节点，每个节点包含一个偏振纠缠光子对源和一个带宽高达 1 GHz 的固态量子存储器。中间站的联合贝尔态测量预示着两个量子存储器之间最大纠缠态的成功分布，保真度为 80.4 ± 2.2%（±1 标准差）。这里展示的量子节点和通道可以作为量子中继器的基本链路。此外，节点中使用的宽带吸收式量子存储器与确定性纠缠源兼容，可同时支持多路复用，为构建实用的固态量子中继器和高速量子网络铺平了道路。