Superconducting circuits are an extremely versatile platform to realize quantum information hardware and to emulate topological materials. We here show how a simple arrangement of capacitors and conventional superconductor-insulator-superconductor junctions can realize an even broader class of systems, in the form of a nonlinear capacitive element which is quasiperiodic with respect to the quantized Cooper-pair charge. Our setup allows to create protected Dirac points defined in the transport degrees of freedom, whose presence leads to a suppression of the classical finite-frequency current noise. Furthermore, the quasiperiodicity can emulate Anderson localization in charge space, measurable via vanishing charge quantum fluctuations. The realization by means of the macroscopic transport degrees of freedom allows for a straightforward generalization to arbitrary dimensions and implements truly non-interacting versions of the considered models. As an outlook, we discuss potential ideas to simulate a transport version of the magic-angle effect known from twisted bilayer graphene.

超导电路是实现量子信息硬件和模拟拓扑材料的极其通用的平台。我们在这里展示了电容器和传统超导体-绝缘体-超导体结的简单布置如何以非线性电容元件的形式实现更广泛的系统，该元件相对于量子化库珀对电荷是准周期的。我们的设置允许创建在传输自由度中定义的受保护狄拉克点，其存在导致经典有限频率电流噪声的抑制。此外，准周期性可以模拟电荷空间中的安德森局域化，可以通过消失的电荷量子涨落来测量。通过宏观传输自由度的实现允许直接推广到任意维度，并实现所考虑模型的真正非交互版本。作为展望，我们讨论了模拟扭曲双层石墨烯中已知的魔角效应的传输版本的潜在想法。