资源环境科技发展态势分析平台

The ability to communicate quantum information over long distances is of central importance in quantum science and engineering(1). Although some applications of quantum communication such as secure quantum key distribution(2,3) are already being successfully deployed(4-7), their range is currently limited by photon losses and cannot be extended using straightforward measure-and-repeat strategies without compromising unconditional security(8). Alternatively, quantum repeaters(9), which utilize intermediate quantum memory nodes and error correction techniques, can extend the range of quantum channels. However, their implementation remains an outstanding challenge(10-16), requiring a combination of efficient and high-fidelity quantum memories, gate operations, and measurements. Here we use a single solid-state spin memory integrated in a nanophotonic diamond resonator(17-19) to implement asynchronous photonic Bell-state measurements, which are a key component of quantum repeaters. In a proof-of-principle experiment, we demonstrate high-fidelity operation that effectively enables quantum communication at a rate that surpasses the ideal loss-equivalent direct-transmission method while operating at megahertz clock speeds. These results represent a crucial step towards practical quantum repeaters and large-scale quantum networks(20,21).

A solid-state spin memory is used to demonstrate quantum repeater functionality, which has the potential to overcome photon losses involved in long-distance transmission of quantum information.

Single-cell RNA sequencing and spatial transcriptomics reveal that the somitogenesis clock is active in mouse gastruloids, which can be induced to generate somites with the correct rostral-caudal patterning.

Gastruloids are three-dimensional aggregates of embryonic stem cells that display key features of mammalian development after implantation, including germ-layer specification and axial organization(1-3). To date, the expression pattern of only a small number of genes in gastruloids has been explored with microscopy, and the extent to which genome-wide expression patterns in gastruloids mimic those in embryos is unclear. Here we compare mouse gastruloids with mouse embryos using single-cell RNA sequencing and spatial transcriptomics. We identify various embryonic cell types that were not previously known to be present in gastruloids, and show that key regulators of somitogenesis are expressed similarly between embryos and gastruloids. Using live imaging, we show that the somitogenesis clock is active in gastruloids and has dynamics that resemble those in vivo. Because gastruloids can be grown in large quantities, we performed a small screen that revealed how reduced FGF signalling induces a short-tail phenotype in embryos. Finally, we demonstrate that embedding in Matrigel induces gastruloids to generate somites with the correct rostral-caudal patterning, which appear sequentially in an anterior-to-posterior direction over time. This study thus shows the power of gastruloids as a model system for exploring development and somitogenesis in vitro in a high-throughput manner.