Topological Plasma Transport from a Diffusion View

Abstract

Recent studies have identified plasma as a topological material. Yet, these researches often depict plasma as a fluid governed by electromagnetic fields, i.e., a classical wave system. Indeed, plasma transport can be characterized by a unique diffusion process distinguished by its collective behaviors. In this work, we adopt a simplified diffusion-migration method to elucidate the topological plasma transport. Drawing parallels to the thermal conduction-convection system, we introduce a double ring model to investigate the plasma density behaviors in the anti-parity-time reversal (APT) unbroken and broken phases. Subsequently, by augmenting the number of rings, we have established a coupled ring chain structure. This structure serves as a medium for realizing the APT symmetric one-dimensional (1D) reciprocal model, representing the simplest tight-binding model with a trivial topology. To develop a model featuring topological properties, we should modify the APT symmetric 1D reciprocal model from the following two aspects: hopping amplitude and onsite potential. From the hopping amplitude, we incorporate the non-reciprocity to facilitate the non-Hermitian skin effect, an intrinsic non-Hermitian topology. Meanwhile, from the onsite potential, the quasiperiodic modulation has been adopted onto the APT symmetric 1D reciprocal model. This APT symmetric 1D Aubry-André-Harper model is of topological nature. Additionally, we suggest the potential applications for these diffusive plasma topological states. This study establishes a diffusion-based approach to realizing topological states in plasma, potentially inspiring further advancements in plasma physics.

Spatiotemporal diffusion metamaterials: Theories and applications

“…In contrast to wave processes, diffusion systems have distinctly different governing equations and application scenarios. Diffusionics 10,11 has emerged to manipulate heat 12 and other energy 13 and mass diffusions. Diffusion metamaterials [14][15][16] usually feature timedependent yet frequency-independent characteristic lengths.…”

Localization Dynamics at the Exceptional Point of Non-Hermitian Creutz Ladder

“…Recent advances in non-Hermitian physics have highlighted deviations from the established principle of bulk-boundary correspondence, [35][36][37][38] with new phenomena such as the non-Hermitian skin effect fundamentally changing the understanding of edge states. [39][40][41][42][43][44] These studies indicate that in non-Hermitian systems, [42][43][44][45][46][47][48][49][50][51][52][53][54][55][56][57][58][59][60] topological invariants and edge states are affected by unique symmetries and conditions, leading to unconventional localization phenomena. [38] Flat bands are dispersionless and can be found in various one-dimensional (1D) and two-dimensional (2D) lattices.…”