Fractional quantum transport and staggered topological transition in a lossy trimerized lattice

Year: 2019

Authors: Du L., Wu JH., Artoni M., La Rocca G.C.

Autors Affiliation: Northeast Normal Univ, Ctr Quantum Sci & Sch Phys, Changchun 130117, Jilin, Peoples R China; Beijing Computat Sci Res Ctr, Beijing 100193, Peoples R China; Brescia Univ, Dept Engn & Informat Technol, I-25133 Brescia, Italy; Brescia Univ, INO CNR Sensor Lab, I-25133 Brescia, Italy; Scuola Normale Super Pisa, I-56126 Pisa, Italy; CNISM, I-56126 Pisa, Italy.

Abstract: Transport in a non-Hermitian trimerized lattice with one lossy site per unit cell exhibits a quantized mean displacement before decay characterized by a two-step phase transition from zero to unity through a fractional value. Such a peculiar behavior, sensitive to both the lattice parameters and the initial state, is shown to be closely related to the presence of two nondegenerate dark states decoupled from the lossy sites and correspond to two staggered band closing points. We further check that distinct topological phases can also be characterized by the total Zak phase and by the number of midgap edge states. Moreover, we demonstrate that the edge states are topologically protected and their localization can be controlled via the couplings imbalance. Our results are expected to be relevant for implementations of topological photonics such as those based on arrays of evanescently coupled waveguides.

Journal/Review: PHYSICAL REVIEW A

Volume: 100 (5)      Pages from: 052102-1  to: 052102-9

More Information: This work is supported by the National Natural Science Foundation of China (No. 10534002 and No. 11674049); the Cooperative Program by the Italian Ministry of Foreign Affairs and International Cooperation (No. PGR00960) and the National Natural Science Foundation of China (No. 11861131001).
KeyWords: ZAK PHASE; LOCALIZATION
DOI: 10.1103/PhysRevA.100.052102

Citations: 10
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