Topological Defect Engineering and PT Symmetry in Non-Hermitian Electrical Circuits.

@article{Stegmaier2021TopologicalDE,
  title={Topological Defect Engineering and PT Symmetry in Non-Hermitian Electrical Circuits.},
  author={Alexander Stegmaier and Stefan Imhof and Tobias Helbig and Tobias Hofmann and Ching Hua Lee and Mark Kremer and Alexander Fritzsche and Thorsten Feichtner and Sebastian Klembt and S. Hofling and Igor Boettcher and Ion Cosma Fulga and Oliver G. Schmidt and Martin Greiter and Tobias Kie{\ss}ling and Alexander Szameit and Ronny Thomale},
  journal={Physical review letters},
  year={2021},
  volume={126 21},
  pages={
          215302
        }
}
We employ electric circuit networks to study topological states of matter in non-Hermitian systems enriched by parity-time symmetry PT and chiral symmetry anti-PT (APT). The topological structure manifests itself in the complex admittance bands which yields excellent measurability and signal to noise ratio. We analyze the impact of PT-symmetric gain and loss on localized edge and defect states in a non-Hermitian Su-Schrieffer-Heeger (SSH) circuit. We realize all three symmetry phases of the… 

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References

SHOWING 1-10 OF 78 REFERENCES
Observation of an anti-PT-symmetric exceptional point and energy-difference conserving dynamics in electrical circuit resonators
TLDR
An electrical circuit producing key non-Hermitian properties and unusual wave dynamics grounded on anti-PT (APT) symmetry is experimentally demonstrated and unique properties of APT-symmetric systems are experimentally confirmed.
Topologically protected bound states in photonic parity-time-symmetric crystals.
TLDR
This work shows theoretically and experimentally the existence of states that are localized at the interface between two topologically distinct PT-symmetric photonic lattices, and finds analytical closed form solutions of topological PT-Symmetric interface states.
Selective enhancement of topologically induced interface states in a dielectric resonator chain
TLDR
A topologically induced defect state is realized in a chain of dielectric microwave resonators and it is shown that the functionality of the system can be enhanced by supplementing topological protection with non-hermitian symmetries that do not have an electronic counterpart.
Topolectrical-circuit realization of topological corner modes
Quantized electric quadrupole insulators have recently been proposed as novel quantum states of matter in two spatial dimensions. Gapped otherwise, they can feature zero-dimensional topological
A quantized microwave quadrupole insulator with topologically protected corner states
TLDR
This work demonstrates experimentally a member of this predicted class of materials—a quantized quadrupole topological insulator—produced using a gigahertz-frequency reconfigurable microwave circuit, and provides conclusive evidence of a unique form of robustness against disorder and deformation, which is characteristic of higher-order topologicalinsulators.
Circuit implementation of a four-dimensional topological insulator
TLDR
Here, Wang et al. realise a four-dimensional topological insulator associated with a nonzero second Chern number using electric circuits, which paves the way to the use of electric circuits for exploring high-dimensionalTopological models.
Topological edge states of interacting photon pairs emulated in a topolectrical circuit
TLDR
A classical structure based on topolectrical circuits is designed 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, emulating two-Photon topological bound states in 1D using a 2D electrical circuit.
Generalized bulk–boundary correspondence in non-Hermitian topolectrical circuits
The study of the laws of nature has traditionally been pursued in the limit of isolated systems, where energy is conserved. This is not always a valid approximation, however, as the inclusion of
Self-induced topological protection in nonlinear circuit arrays
The interplay between topology and many-body physics has been a topic of strong interest in condensed matter physics for several years. For electronic systems, research has so far focused on linear
Impurity induced scale-free localization
Non-Hermitian systems have been shown to have a dramatic sensitivity to their boundary conditions. In particular, the non-Hermitian skin effect induces collective boundary localization upon turning
...
...