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

Alexander Stegmaier, Stefan Imhof, Tobias Helbig, Tobias Hofmann, Ching Hua Lee, Mark Kremer, Alexander Fritzsche, Thorsten Feichtner, Sebastian Klembt, Sven Höfling, Igor Boettcher, Ion Cosma Fulga, Libo Ma, Oliver G. Schmidt, Martin Greiter, Tobias Kiessling, Alexander Szameit, and Ronny Thomale
Phys. Rev. Lett. 126, 215302 – Published 28 May 2021
PDFHTMLExport Citation

Abstract

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 system, including the APT-symmetric regime that occurs at large gain and loss. We measure the admittance spectrum and eigenstates for arbitrary boundary conditions, which allows us to resolve not only topological edge states, but also a novel PT-symmetric Z2 invariant of the bulk. We discover the distinct properties of topological edge states and defect states in the phase diagram. In the regime that is not PT symmetric, the topological defect state disappears and only reemerges when APT symmetry is reached, while the topological edge states always prevail and only experience a shift in eigenvalue. Our findings unveil a future route for topological defect engineering and tuning in non-Hermitian systems of arbitrary dimension.

  • Figure
  • Figure
  • Figure
  • Received 10 November 2020
  • Accepted 21 April 2021

DOI:https://doi.org/10.1103/PhysRevLett.126.215302

© 2021 American Physical Society

Physics Subject Headings (PhySH)

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

Alexander Stegmaier1, Stefan Imhof2, Tobias Helbig1, Tobias Hofmann1, Ching Hua Lee3, Mark Kremer4, Alexander Fritzsche4,1, Thorsten Feichtner5, Sebastian Klembt6, Sven Höfling2, Igor Boettcher7, Ion Cosma Fulga8, Libo Ma9, Oliver G. Schmidt9, Martin Greiter1, Tobias Kiessling2, Alexander Szameit4, and Ronny Thomale1

  • 1Institute for Theoretical Physics and Astrophysics, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany
  • 2Physikalisches Institut and Röntgen Research Center for Complex Material Systems, Universität Würzburg, D-97074 Würzburg, Germany
  • 3Department of Physics, National University of Singapore, Singapore 117542
  • 4Institut für Physik, Universität Rostock, Albert-Einstein-Straße 23, 18059 Rostock
  • 5Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci, 3220133 Milano, Italy
  • 6Technische Physik and Wilhelm-Conrad-Röntgen-Research Center for Complex Material Systems, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
  • 7Joint Quantum Institute, University of Maryland, College Park, Maryland 20742, USA
  • 8Institute for Theoretical Solid State Physics, IFW Dresden, 01171 Dresden, Germany
  • 9Institute for Integrative Nanosciences, Leibniz IFW Dresden, 01069 Dresden, Germany

Article Text (Subscription Required)

Click to Expand

Supplemental Material (Subscription Required)

Click to Expand

References (Subscription Required)

Click to Expand
Issue

Vol. 126, Iss. 21 — 28 May 2021

Reuse & Permissions
Access Options
CHORUS

Article Available via CHORUS

Download Accepted Manuscript

Authorization Required


×
×

Images

×

Sign up to receive regular email alerts from Physical Review Letters

Log In

Cancel
×

Search


Article Lookup

Paste a citation or DOI

Enter a citation
×