Regensburg 2022 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 37: Superconducting Electronics: SQUIDs, Qubits, Circuit QED
TT 37.14: Vortrag
Freitag, 9. September 2022, 13:00–13:15, H22
Dirac physics and charge localization due to quasiperiodic nonlinear capacitances — •Tobias Herrig1, Jedediah Pixeley2, Elio König3, and Roman-Pascal Riwar1 — 1Forschungszentrum Jülich, Germany — 2Rutgers University, Piscataway, New Jersey, USA — 3Max-Planck Institute, Stuttgart, Germany
Superconducting circuits are an extremely versatile platform to realize quantum information hardware, and, as was recently realized, to emulate topological materials, such as Weyl semimetals or Chern insulators. We here show how a simple arrangement of capacitors and conventional SIS junctions can realize a nonlinear capacitive element with a suprising property: it can be quasiperiodic with respect to the quantized Cooper-pair charge. Integrating this element into a larger circuit opens the door towards the engineering of an even broader class of systems. First, we use it to simulate a protected Dirac material defined in the transport degrees of freedom. The presence of the Dirac point leads to a suppression of the classical part of the finite-frequency noise. Second, we are able to exploit the quasiperiodicity to implement the Aubry-André model, and therebey to emulate Anderson localization in charge space. Our setup implements a truly non-interacting version of the model, in which the macroscopic quantum mechanics of the circuit already incorporates microscopic interaction effects. This should be contrasted to conventional solid state and cold atomic realizations, where competition between interaction and localization are a common side effect. We predict that quantum charge fluctuations directly probe the localization effect.