Topological Defect Engineering and $$\mathcal{PT}$$ Symmetry in Non-Hermitian Electrical Circuits
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- Univ. of Wurzburg (Germany)
- National Univ. of Singapore (Singapore)
- Universität Rostock (Germany)
- Universität Rostock (Germany); Univ. of Wurzburg (Germany)
- Politecnico di Milano (Italy)
- Univ. of Maryland, College Park, MD (United States)
- Leibniz Institute for Solid State and Materials Research (IFW Dresden) (Germany)
In this work, we employ electric circuit networks to study topological states of matter in non-Hermitian systems enriched by parity-time symmetry $$\mathcal{PT}$$ and chiral symmetry anti-$$\mathcal{PT (APT)}$$. The topological structure manifests itself in the complex admittance bands which yields excellent measurability and signal to noise ratio. We analyze the impact of $$\mathcal{PT}$$-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 $$\mathcal{APT}$$-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 $$\mathcal{PT}$$-symmetric $$\mathbb{Z}_2$$ 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 $$\mathcal{PT}$$ symmetric, the topological defect state disappears and only reemerges when $$\mathcal{APT}$$ 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.
- Research Organization:
- Univ. of Maryland, College Park, MD (United States); Duke Univ., Durham, NC (United States)
- Sponsoring Organization:
- German Research Foundation (DFG); Studienstiftung des deutschen Volkes; USDOE Office of Science (SC), Basic Energy Sciences (BES); National Science Foundation (NSF); USDOE Office of Science (SC), Advanced Scientific Computing Research (ASCR); US Air Force Office of Scientific Research (AFOSR); US Army Research Office (ARO); US Army Research Laboratory (USARL); Alfried Krupp von Bohlen and Halbach Foundation
- Grant/Contract Number:
- SC0019040; SC0019449; SC0020312; BL 574/13-1; SZ 276/15-1; SZ 276/19-1; SZ 276/20-1
- OSTI ID:
- 1852783
- Journal Information:
- Physical Review Letters, Vol. 126, Issue 21; ISSN 0031-9007
- Publisher:
- American Physical Society (APS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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