Giant Isolation and Pure Gyration in a Superconducting Resonator Chain

Non-reciprocity is vital for protecting superconducting quantum devices from undesired back-propagation and fluctuations, but efficient scaling requires doing so with a compact footprint. Currently, non-reciprocal devices that use the Faraday effect require substantial magnetic shielding, thus limiting the quantity that can be housed in a dilution refrigerator. Here we experimentally demonstrate giant isolation and pure gyration, i.e. free from any amplitude contrast, in a spatio-temporally modulated superconducting resonator chain fabricated entirely on-chip. Such chains can be modeled as a Hatano-Nelson system [1], which elucidates the origin of the non-reciprocity—specifically isolation and gyration—and the intricate interplay between them. This result marks a crucial step forward in designing and implementing practical, highly directional non-reciprocal devices that are on-chip integrable with existing superconducting circuits.

[1] O. E. Orsel, J. Noh, P. Zhu, J. Yim, T. L. Hughes, R. Thomale, and G. Bahl, Giant non-reciprocity and gyration through modulation-induced Hatano-Nelson coupling in integrated photonics, arXiv:2410.10079.