Physikalisches Institut, Karlsruhe Institute of Technology, D-76131, Karlsruhe, Germany.
Russian Quantum Center, National University of Science and Technology MISIS, Moscow, 119049, Russia.
Nat Commun. 2018 Jan 11;9(1):150. doi: 10.1038/s41467-017-02608-8.
Quantum theory is expected to govern the electromagnetic properties of a quantum metamaterial, an artificially fabricated medium composed of many quantum objects acting as artificial atoms. Propagation of electromagnetic waves through such a medium is accompanied by excitations of intrinsic quantum transitions within individual meta-atoms and modes corresponding to the interactions between them. Here we demonstrate an experiment in which an array of double-loop type superconducting flux qubits is embedded into a microwave transmission line. We observe that in a broad frequency range the transmission coefficient through the metamaterial periodically depends on externally applied magnetic field. Field-controlled switching of the ground state of the meta-atoms induces a large suppression of the transmission. Moreover, the excitation of meta-atoms in the array leads to a large resonant enhancement of the transmission. We anticipate possible applications of the observed frequency-tunable transparency in superconducting quantum networks.
量子理论预计将控制量子超材料的电磁特性，量子超材料是由许多充当人造原子的量子物体组成的人工制造介质。电磁波通过这种介质传播时，会伴随着单个超原子内部固有量子跃迁以及对应于它们之间相互作用的模式的激发。在这里，我们演示了一个实验，其中将一组双环型超导磁通量子比特嵌入到微波传输线中。我们观察到，在很宽的频率范围内，通过超材料的传输系数周期性地依赖于外部施加的磁场。在控制超原子基态的磁场下，诱导了传输的大抑制。此外，阵列中超原子的激发导致了传输的大共振增强。我们预计在超导量子网络中，观察到的可调谐透明性可能有一些应用。
