一维耦合腔晶格中磁子-光子拓扑相变和拓扑量子态的调制

Modulation of topological phase transition and topological quantum state of magnon-photon in one-dimensional coupled cavity lattices

本文提出了基于耦合腔的一维晶格理论方案,其中每个晶胞包含微波腔光子和磁子,通过调控磁子与微波光子的耦合来研究系统中的拓扑相变和拓扑量子通道.首先,分析了在奇偶晶格数情况下,系统能谱和边缘态的特征,并发现边缘态分布可以展示反转过程,可以实现多通道拓扑量子态传输;其次,考虑存在缺陷和无序的扰动,发现它们在较小值范围内,可以使能带产生波动和翻转现象,但边缘状态对其是鲁棒的,这表明边缘态受到系统的拓扑保护.该研究结果为研究拓扑磁子-光子提供了一条新途径,将在量子信息处理中有着广阔的应用前景.

We propose a theoretical scheme to study the topological properties of magnon-photon in a one-dimensional coupled cavity lattice.Each unit cell is composed of the cavity microwave photon and the magnon,where the magnon is placed inside the cavity.The coupling of cavity microwave photon and magnon is controlled by an external magnetic field,and multiple cavities are coupled with each other to form a one-dimensional coupled cavity lattice system.Here,we study the topological phase transition and topological quantum channels of magnon-photon in the system by adjusting the magnon-photon coupling.Firstly,considering odd and even number lattices,we analyze and discuss the energy spectrum and the edge state in one-dimensional coupled cavity lattices.It is found that the energy band of the system is symmetric,and the edge states in the energy gap have time reversal symmetry,which makes the system topologically protected.At the same time,it is also noted that the maximum value,flipping,and period of the energy spectrum have changed,and the region of the edge state has expanded and extended.In addition,the edge state distribution can undergo the flipping process,which can achieve multi-channel topological quantum state transmission.Besides,considering the presence of defects and disorder in the system,it is found that when the random defect potential is small,the edge state of the system is robust to it,but when the random defect potential is large,the fluctuation of the energy band will be enhanced,and the edge state will be submerged in the energy band.However,when the disorder is very small,it can cause band fluctuations and flipping phenomena,and the edge state is robust to it,indicating the topological protection of the edge state.This work offers an effective way to study topological magnon-photon,which will have promising applications in quantum information processing.