Olekhno Nikita A, Kretov Egor I, Stepanenko Andrei A, Ivanova Polina A, Yaroshenko Vitaly V, Puhtina Ekaterina M, Filonov Dmitry S, Cappello Barbara, Matekovits Ladislau, Gorlach Maxim A
Department of Physics and Engineering, ITMO University, Saint Petersburg, 197101, Russia.
Center for Photonics and 2D Materials, Moscow Institute of Physics and Technology, Dolgoprudny, 141700, Russia.
Nat Commun. 2020 Mar 18;11(1):1436. doi: 10.1038/s41467-020-14994-7.
Topological physics opens up a plethora of exciting phenomena allowing to engineer disorder-robust unidirectional flows of light. Recent advances in topological protection of electromagnetic waves suggest that even richer functionalities can be achieved by realizing topological states of quantum light. This area, however, remains largely uncharted due to the number of experimental challenges. Here, we take an alternative route and design a classical structure based on topolectrical circuits which serves as a simulator of a quantum-optical one-dimensional system featuring the topological state of two photons induced by the effective photon-photon interaction. Employing the correspondence between the eigenstates of the original problem and circuit modes, we use the designed simulator to extract the frequencies of bulk and edge two-photon bound states and evaluate the topological invariant directly from the measurements. Furthermore, we perform a reconstruction of the two-photon probability distribution for the topological state associated with one of the circuit eigenmodes.
拓扑物理学揭示了大量令人兴奋的现象，使得人们能够设计出对无序具有鲁棒性的单向光流。电磁波拓扑保护方面的最新进展表明，通过实现量子光的拓扑态，可以实现更为丰富的功能。然而，由于诸多实验挑战，这一领域在很大程度上仍未被探索。在此，我们采用另一种途径，设计了一种基于拓扑电路的经典结构，该结构可作为量子光学一维系统的模拟器，其具有由有效光子 - 光子相互作用诱导的双光子拓扑态。利用原始问题的本征态与电路模式之间的对应关系，我们使用所设计的模拟器来提取体态和边缘双光子束缚态的频率，并直接从测量结果中评估拓扑不变量。此外，我们对与电路本征模式之一相关的拓扑态进行了双光子概率分布的重构。
