qth-root non-Hermitian Floquet topological insulators

Longwen Zhou*, Raditya Weda Bomantara, Shenlin Wu

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

9 Scopus citations


Floquet phases of matter have attracted great attention due to their dynamical and topological nature that are unique to nonequilibrium settings. In this work, we introduce a generic way of taking any integer qth-root of the evolution operator U that describes Floquet topological matter. We further apply our qth-rooting procedure to obtain 2nth- and 3nth-root first- and second-order non-Hermitian Floquet topological insulators (FTIs). There, we explicitly demonstrate the presence of multiple edge and corner modes at fractional quasienergies ±(0, 1, ...2n)π/2n and ±(0, 1, ..., 3n)π/3n, whose numbers are highly controllable and capturable by the topological invariants of their parent systems. Notably, we observe non-Hermiticity induced fractional-quasienergy corner modes and the coexistence of non-Hermitian skin effect with fractional-quasienergy edge states. Our findings thus establish a framework of constructing an intriguing class of topological matter in Floquet open systems.

Original languageEnglish
Article number015
JournalSciPost Physics
Issue number2
StatePublished - Aug 2022
Externally publishedYes

Bibliographical note

Funding Information:
Funding information L.Z. is supported by the National Natural Science Foundation of China (Grant No. 11905211), the Young Talents Project at Ocean University of China (Grant No. 861801013196), and the Applied Research Project of Postdoctoral Fellows in Qingdao (Grant No. 861905040009). R.W.B. is supported by the Australian Research Council Centre of Excellence for Engineered Quantum Systems (EQUS, CE170100009).

Publisher Copyright:
Copyright L. Zhou et al.

ASJC Scopus subject areas

  • Physics and Astronomy (all)


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