open access

https://hdl.handle.net/2115/92721

Dual symmetry classification of non-Hermitian systems and Z2 point-gap topology of a nonunitary quantum walk

英語

2024-06-15

American Physical Society (APS)

Physical Review B

109(23)

235408

Non-Hermitian systems exhibit richer topological properties compared to their Hermitian counterparts. It is well known that non-Hermitian systems have been classified based on either the symmetry relations for nonHermitian Hamiltonians or the symmetry relations for nonunitary time-evolution operators in the context of Floquet topological phases. In this work, we propose that non-Hermitian systems can always be classified in two ways; a non-Hermitian system can be classified using the symmetry relations for non-Hermitian Hamiltonians or time-evolution operator regardless of the Floquet topological phases or not. We refer to this as dual symmetry classification. To demonstrate this, we successfully introduce a nonunitary quantum walk that exhibits point gaps with a Z2 point-gap topological phase applying the dual symmetry classification and treating the time-evolution operator of this quantum walk as the non-Hermitian Hamiltonian.

学術雑誌論文

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©[2024] American Physical Society

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