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Anomalous pumping in the non-Hermitian Rice-Mele model.

Journal of physics. Condensed matter : an Institute of Physics journal·2025
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Anomalous pumping in the non-Hermitian Rice-Mele model.

Abhishek Kumar1,2, Sarbajit Mazumdar1,3, S D Mahanti4

  • 1National Institute of Science Education and Research, Jatni, Odisha 752050, India.

Journal of Physics. Condensed Matter : an Institute of Physics Journal
|January 17, 2025
PubMed
Summary

Topological charge pumping in the Rice-Mele model is explored with non-Hermiticity. Anomalous pumping emerges with increasing non-Hermitian parameter γ, defying Hermitian counterparts.

Keywords:
anomalous pumpingbulk-boundary correspondencenon-Bloch Chern numbernon-Hermitian topology

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Area of Science:

  • Condensed Matter Physics
  • Topological Materials
  • Non-Hermitian Systems

Background:

  • Topological charge pumping describes particle transport in materials with non-trivial topology.
  • Non-Hermitian systems exhibit unique phenomena like skin effects and exceptional points.
  • The Rice-Mele model is a fundamental model for studying topological phases.

Purpose of the Study:

  • Investigate topological charge pumping in the non-Hermitian Rice-Mele model.
  • Understand the role of non-Hermiticity, skin effects, and exceptional points in pumping dynamics.
  • Explore novel pumping phenomena and topological transitions driven by non-Hermitian parameters.

Main Methods:

  • Finite-size generalized Brillouin zone scheme to distinguish edge and skin modes.
  • Analysis of topological transitions driven by non-Hermitian parameter γ and system size N.
  • Reformulation of a non-Bloch topological invariant for 1+1D systems.

Main Results:

  • Identified γ and N as tuning knobs for topological transitions in the static 1D Rice-Mele model.
  • Demonstrated adiabatic pumping survival with finite γ, dependent on driving protocols.
  • Observed anomalous pumping and trivial adiabatic pumping due to non-Hermiticity and point gap physics.

Conclusions:

  • Non-Hermiticity fundamentally alters topological charge pumping in the Rice-Mele model.
  • Anomalous and trivial pumping phenomena arise from non-Hermitian skin effects and point gap topology.
  • A reformulated non-Bloch invariant accurately predicts pumped charges in non-Hermitian systems.