Non-Bloch-Band Collapse and Chiral Zener Tunneling

Area of Science:

• Condensed Matter Physics
• Topological Materials
• Quantum Dynamics

Background:

• Non-Bloch-band theory explains bulk properties and topological invariants in non-Hermitian crystals with open boundaries.
• The skin effect causes bulk eigenstates to localize at the edges, a phenomenon not fully integrated with Bloch dynamics.
• The interplay between non-Bloch-band theory, skin effect, and coherent Bloch dynamics remains largely unexplored.

Purpose of the Study:

• To investigate the unexplored interplay between non-Bloch-band theory, the skin effect, and coherent Bloch dynamics in non-Hermitian lattices.
• To analyze how the collapse of non-Bloch bands and skin modes affects Bloch dynamics under external forces.
• To explore phenomena arising from resonance forcing in these systems.

Main Methods:

• Theoretical analysis of two-band non-Hermitian lattices.
• Investigation of Bloch dynamics under external forces, particularly resonance forcing.
• Examination of non-Bloch band collapse and its impact on eigenstates and energy spectra.

Main Results:

• The collapse of non-Bloch bands and skin modes significantly alters Bloch dynamics in the presence of an external force.
• Resonance forcing leads to the coalescence of Wannier-Stark ladders.
• Chiral Zener tunneling occurs between the two dispersive Bloch bands due to band collapse.

Conclusions:

• The study reveals a deep connection between non-Bloch-band collapse, skin effects, and coherent Bloch dynamics.
• Wannier-Stark ladder coalescence and chiral Zener tunneling are key emergent phenomena under resonance forcing.
• This work provides new insights into the behavior of non-Hermitian systems with open boundaries.