Non-reciprocity of signal transmission enhances capacity of communication channels and protects transmission quality against possible signal instabilities, thus becoming an important component ensuring coherent information processing. However, non-reciprocal transmission requires breaking time-reversal symmetry (TRS) which poses challenges of both practical and fundamental character hindering the progress. Here we report a new scheme for achieving broadband non-reciprocity using a specially engineered hybrid microwave cavity. The TRS breaking is realized via strong coherent coupling between a selected chiral mode in the microwave cavity and a single collective spin excitation (magnon) in a ferromagnetic yttrium iron garnet (YIG) sphere. The non-reciprocity in transmission is observed spanning nearly a 0.5 GHz frequency band, which outperforms by two orders of magnitude the previously achieved bandwidths. Our findings open new directions for robust coherent information processing in a broad range of systems in both classical and quantum regimes.

中文翻译：

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磁振子和微波光子的强耦合实现宽带互惠

信号传输的互惠性提高了通信信道的容量，并保护传输质量免受可能的信号不稳定性的影响，因此成为确保相干信息处理的重要组成部分。然而，不可逆传输需要打破时间反转对称性（TRS），这带来了阻碍发展的实际和基本特征的挑战。在这里，我们报告了一种使用特殊设计的混合微波腔体实现宽带互惠的新方案。TRS断裂是通过微波腔体中选定的手性模式与铁磁性钇铁石榴石（YIG）球体中的单个集体自旋激发（磁振子）之间的强相干耦合实现的。在几乎0.5 GHz的频率范围内观察到传输的不可逆性，它比以前达到的带宽高两个数量级。我们的发现为在经典和量子机制下的广泛系统中进行健壮的相干信息处理开辟了新的方向。