Selective and tunable excitation of topological nonHermitian quasiedge modes
Abstract
NonHermitian lattices under semiinfinite boundary conditions sustain an extensive number of exponentially localized states, dubbed nonHermitian quasiedge modes. Quasiedge states arise rather generally in systems displaying the nonHermitian skin effect and can be predicted from the nontrivial topology of the energy spectrum under periodic boundary conditions via a bulkedge correspondence. However, the selective excitation of the system in one among the infinitely many topological quasiedge states is challenging both from practical and conceptual viewpoints. In fact, in any realistic system with a finite lattice size most of the quasiedge states collapse and become metastable states. Here we suggest a route toward the selective and tunable excitation of topological quasiedge states that avoids the collapse problem by emulating semiinfinite lattice boundaries via tailored onsite potentials at the edges of a finite lattice. We illustrate such a strategy by considering a nonHermitian topological interface obtained by connecting two HatanoNelson chains with opposite imaginary gauge fields, which is amenable for a full analytical treatment.
 Publication:

Proceedings of the Royal Society of London Series A
 Pub Date:
 May 2022
 DOI:
 10.1098/rspa.2021.0927
 arXiv:
 arXiv:2112.04988
 Bibcode:
 2022RSPSA.47810927L
 Keywords:

 Quantum Physics;
 Condensed Matter  Strongly Correlated Electrons;
 Physics  Optics
 EPrint:
 14 pages, 7 figures, under review by Proceedings of the Royal Society A