arXiv subjects

Xianhao Rao

Publications and source records attributed to Xianhao Rao.

4 recordsLinked to original sources

arXiv2026

Collisionless Resonances Set the Size of a Weyl Exceptional Ring

Eliminating continuum degrees of freedom converts conservative dynamics into a dispersive, non-Hermitian response whose topology need not represent the causally selected kinetic dynamics. In collisionless magnetized plasma, retarded Landau and cyclotron resonances damp two Weyl modes differently and replace a cold Weyl point by an exceptional ring. Axial roots and root-normalized polarization mixing predict its off-axis radius, $R_{\rm EP}^{\rm pred}=|ΔΓ|/(2|v_{\rm mix}|)$, before any double root is computed. Across five nonrelativistic scans spanning a 310-fold range of differential damping, $R_{\rm EP}^{\rm pred}$ agrees with the nonlinear double-root radius $R_{\rm EP}^{\rm full}$ within $0.12\%$. The selected retarded kinetic-response bundle is a continuous graph over the electric root line bundle and has the same first Chern class under stated conditions. The cold interface mode continues to a localized Keldysh pole with one oriented crossing in the tested line-gap window, consistent with the inherited charge.

physics.plasm-ph↗

arXiv2026

Phase-Space Topology and Spectral Flow in Screened Magnetized Plasmas

Topological wave phenomena in continuous media are fundamentally challenged by unbounded spectra and the absence of a compact Brillouin zone, which obstruct conventional bulk--interface formulations. We develop a unified phase-space framework for screened magnetized plasma based on a pseudo-Hermitian formulation with a positive-definite metric, enabling a generalized Schrödinger description and a Weyl-symbol analysis of the bulk generator. We show that the bulk symbol hosts isolated band degeneracies acting as Berry--Chern monopoles, including a higher-order spin-1 degeneracy with topological charge $+2$ that generically splits into two spin-$\tfrac{1}{2}$ Weyl points under symmetry breaking. To characterize topology in this noncompact setting, we introduce a strip-gap Chern number associated with finite real-frequency strips of the bulk spectrum, extending band Chern topology to continuum systems. This invariant governs the spectral flow of interface modes induced by spatial variations of the magnetic field and establishes a bulk--interface correspondence at the level of phase-space symbols. By solving the interface eigenvalue problem, we demonstrate that the net spectral flow across the strip gap is determined by the enclosed monopole charge. We further show that this correspondence persists under collisional damping, provided that a finite strip gap remains and no exceptional points enter it. Our results provide a systematic phase-space framework for topological wave transport in continuous media beyond compact-band and idealized Hermitian settings.

cond-mat.mes-hall↗

arXiv2025

Symmetry-Driven Bulk-Edge Correspondence in Electron Magnetofluids at Finite Temperature

We present a theoretical framework connecting the pseudo-Chern number in momentum space to the spectral flow index in phase space for continuous media, with specific applications to topological Langmuir-cyclotron waves (TLCWs) in magnetized plasmas at uniform finite temperatures. By deriving a rigorous correspondence between these two topological invariants, we provide a solid justification for previous studies that applied this relationship heuristically across various continuous media. For magnetized plasmas with finite-temperature effects, we confirm the existence of TLCWs through numerical computation of bulk Chern number differences and analytical calculation of the spectral flow index. These findings advance the understanding of topological phenomena in continuous media.

physics.plasm-ph↗

arXiv2024

Relaxation model for a homogeneous plasma with spherically symmetric velocity space

We derive the transport equations from the Vlasov-Fokker-Planck equation when the velocity space is spherically symmetric. The Shkarofsky's form of Fokker-Planck-Rosenbluth collision operator is employed in the Vlasov-Fokker-Planck equation. A closed-form relaxation model for homogeneous plasmas could be presented in terms of Gauss hypergeometric2F1 functions. This has been accomplished based on the Maxwellian mixture model. Furthermore, we demonstrate that classic models such as two-temperature thermal equilibrium model and thermodynamic equilibrium model are special cases of our relaxation model and the zeroth-order Braginskii heat transfer model can also be derived. The present relaxation model is a nonequilibrium model based on the hypothesis that the plasmas system possesses finitely distinguishable independent features, without relying on the conventional near-equilibrium assumption.

physics.plasm-ph↗