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arXiv · 2109.01325

Non-Hermitian topological phase transitions in superlattices and the optical Dirac equation

Stefano Longhi
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Abstract

Optical superlattices with sublattice symmetry subjected to a synthetic imaginary gauge field undergo a topological phase transition in the Bloch energy spectrum, characterized by the change of a spectral winding number. For a narrow gap, the phase transition is of universal form and described by a non-Hermitian Dirac equation with Lorentz-symmetry violation. A simple photonic system displaying such a phase transition is discussed, which is based on light coupling in co-propagating gratings.

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Stefano Longhi. 2021-09-03. Non-Hermitian topological phase transitions in superlattices and the optical Dirac equation. https://doi.org/10.1364/ol.440052

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