1. Su-Schrieffer-Heeger chain with one pair of $$\mathcal{P}\mathcal{T}$$ 𝒫 𝒯 -symmetric defects
- Author
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L. Jin, P. Wang, and Z. Song
- Subjects
Medicine ,Science - Abstract
Abstract The topologically nontrivial edge states induce $$\mathcal{P}\mathcal{T}$$ 𝒫 𝒯 transition in Su-Schrieffer-Heeger (SSH) chain with one pair of gain and loss at boundaries. In this study, we investigated a pair of $$\mathcal{P}\mathcal{T}$$ 𝒫 𝒯 -symmetric defects located inside the SSH chain, in particular, the defects locations are at the chain centre. The $$\mathcal{P}\mathcal{T}$$ 𝒫 𝒯 symmetry breaking of the bound states leads to the $$\mathcal{P}\mathcal{T}$$ 𝒫 𝒯 transition, the $$\mathcal{P}\mathcal{T}$$ 𝒫 𝒯 -symmetric phases and the localized states were studied. In the broken $$\mathcal{P}\mathcal{T}$$ 𝒫 𝒯 -symmetric phase, all energy levels break simultaneously in topologically trivial phase; however, two edge states in topologically nontrivial phase are free from the influence of the $$\mathcal{P}\mathcal{T}$$ 𝒫 𝒯 -symmetric defects. We discovered $$\mathcal{P}\mathcal{T}$$ 𝒫 𝒯 -symmetric bound states induced by the $$\mathcal{P}\mathcal{T}$$ 𝒫 𝒯 -symmetric local defects at the SSH chain centre. The $$\mathcal{P}\mathcal{T}$$ 𝒫 𝒯 -symmetric bound states significantly increase the $$\mathcal{P}\mathcal{T}$$ 𝒫 𝒯 transition threshold and coalesce to the topologically protected zero mode with vanishing probabilities on every other site of the left-half chain and the right-half chain, respectively. more...
- Published
- 2017
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