近日，巴西戈亚斯联邦大学的G. M. A. Almeida及其研究小组与塞尔吉普联邦大学的A. M. C. Souza合作并取得一项新进展。经过不懈努力，他们探究无序诱导的平带量子通信。相关研究成果已于2023年8月8日在国际知名学术期刊《物理评论A》上发表。

该研究团队表明量子比特传输协议可以通过一个由无序的XX自旋-1/2金刚石链容纳的平带来实现。在没有无序的情况下，由于紧凑的局域态形成平带，传输变得不可能。当考虑非对角线无序时，尽管保留了带的简并性，但相关态不再局限于单位晶胞。通过将发送端和接收端摄动耦合到平面波段，研究人员得到了一个类似于具有两个集线器的星形网络模型的通用有效哈密顿量。有效耦合对应于和平带模式相关的波函数。这些参数之间的特定关系定义了量子态传输的质量，而量子态传输的质量又与平带中的局域化程度有关。

这一研究发现为在量子通信的背景下进一步研究平带建立了一个框架。

附：英文原文

Title: Flat-band quantum communication induced by disorder

Author: G. M. A. Almeida, R. F. Dutra, A. M. C. Souza, M. L. Lyra, F. A. B. F. de Moura

Issue&Volume: 2023/08/08

Abstract: We show that a qubit transfer protocol can be realized through a flat band hosted by a disordered XX spin-1/2 diamond chain. In the absence of disorder, the transmission becomes impossible due to the compact localized states forming the flat band. When off-diagonal disorder is considered, the degeneracy of the band is preserved but the associated states are no longer confined to the unit cells. By perturbatively coupling the sender and receiver to the flat band, we derive a general effective Hamiltonian resembling a star network model with two hubs. The effective couplings correspond to wave functions associated with the flat-band modes. Specific relationships between these parameters define the quality of the quantum-state transfer which, in turn, are related to the degree of localization in the flat band. Our findings establish a framework for further studies of flat bands in the context of quantum communication.

DOI: 10.1103/PhysRevA.108.022407

Source: https://journals.aps.org/pra/abstract/10.1103/PhysRevA.108.022407