Edge States and Topological Invariants of Non-Hermitian Systems.
Shunyu Yao,Zhong Wang +1 more
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TLDR
This work obtains the phase diagram of the non-Hermitian Su-Schrieffer-Heeger model, whose topological zero modes are determined by theNon-Bloch winding number instead of the Bloch-Hamiltonian-based topological number.Abstract:
The bulk-boundary correspondence is among the central issues of non-Hermitian topological states. We show that a previously overlooked "non-Hermitian skin effect" necessitates redefinition of topological invariants in a generalized Brillouin zone. The resultant phase diagrams dramatically differ from the usual Bloch theory. Specifically, we obtain the phase diagram of the non-Hermitian Su-Schrieffer-Heeger model, whose topological zero modes are determined by the non-Bloch winding number instead of the Bloch-Hamiltonian-based topological number. Our work settles the issue of the breakdown of conventional bulk-boundary correspondence and introduces the non-Bloch bulk-boundary correspondence.read more
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Topological Photonics
Tomoki Ozawa,Hannah M. Price,Alberto Amo,Nathan Goldman,Mohammad Hafezi,Ling Lu,Mikael C. Rechtsman,David Schuster,Jonathan Simon,Oded Zilberberg,Iacopo Carusotto +10 more
TL;DR: Topological photonics is a rapidly emerging field of research in which geometrical and topological ideas are exploited to design and control the behavior of light as mentioned in this paper, which holds great promise for applications.
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Biorthogonal Bulk-Boundary Correspondence in Non-Hermitian Systems.
TL;DR: This work provides a comprehensive framework for generalized bulk-boundary correspondence and a quantized biorthogonal polarization that is formulated directly in systems with open boundaries, including exactly solvable non-Hermitian extensions of the Su-Schrieffer-Heeger model and Chern insulators.
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Exceptional topology of non-Hermitian systems
TL;DR: In this paper, the role of topology in non-Hermitian (NH) systems and its far-reaching physical consequences observable in a range of dissipative settings are reviewed.
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Non-Hermitian Chern Bands
Shunyu Yao,Fei Song,Zhong Wang +2 more
TL;DR: This work introduces non-Bloch Chern numbers that faithfully predict the numbers of chiral edge modes and highlights a unique feature of non-Hermitian bands and suggests a non- Bloch framework to characterize their topology.
References
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M. Z. Hasan,Charles L. Kane +1 more
TL;DR: In this paper, the theoretical foundation for topological insulators and superconductors is reviewed and recent experiments are described in which the signatures of topologically insulators have been observed.
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Xiao-Liang Qi,Shou-Cheng Zhang +1 more
TL;DR: Topological superconductors are new states of quantum matter which cannot be adiabatically connected to conventional insulators and semiconductors and are characterized by a full insulating gap in the bulk and gapless edge or surface states which are protected by time reversal symmetry.
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Real Spectra in Non-Hermitian Hamiltonians Having PT Symmetry
TL;DR: The condition of self-adjointness as discussed by the authors ensures that the eigenvalues of a Hamiltonian are real and bounded below, replacing this condition by the weaker condition of $\mathrm{PT}$ symmetry, one obtains new infinite classes of complex Hamiltonians whose spectra are also real and positive.
Journal ArticleDOI
Observation of parity–time symmetry in optics
Christian E. Rüter,Konstantinos G. Makris,Ramy El-Ganainy,Demetrios N. Christodoulides,Mordechai Segev,Detlef Kip +5 more
TL;DR: In this paper, the authors report the first observation of the behaviour of a PT optical coupled system that judiciously involves a complex index potential, and observe both spontaneous PT symmetry breaking and power oscillations violating left-right symmetry.