arXiv subjects

Si-Wen Li

Publications and source records attributed to Si-Wen Li.

4 recordsLinked to original sources

arXiv2026

Chaos in the near-horizon dynamics of the dyonic $\rm{AdS_4}$-Reissner-Nordström black hole

We investigate the chaos in the dynamics of a probe massless particle confined by the harmonic potential near the horizon of the dyonic $\rm{AdS_4}$-Reissner-Nordström black hole. The total energy of the particle, chemical potential and magnetic field in this system serving as independently adjustable parameters tune nonlinearity and phase-space structure. By analyzing the trajectories on the Poincaré section and evaluating the Lyapunov exponents, we obtain the dynamical phase diagrams of the chaos and find their counteracting regulatory role: at low energy, chaos is enhanced and the Lyapunov exponent $λ_L$ violates its upper bound (i.e. surface gravity) in the extremal black hole limit(combined paramete $Γ=3$); at high energy, the same extremal limit suppresses chaos, with $λ_L$ dropping to zero and a regular dynamical corridor emerging along $Γ=3$ in the dynamical phase diagrams. These results establish a direct mapping between black hole thermodynamics and microscopic chaos, offering new insights into the AdS/QCD correspondence and nonlinear dynamics in strongly curved spacetimes.

hep-th↗

arXiv2024

Holographic spin alignment of $J/ψ$ meson in magnetized plasma

We study the mass spectra and spin alignment of vector meson $J/ψ$ in a thermal magnetized background using a generalized theoretical framework based on gauge/gravity duality. Utilizing a soft wall model for the QGP background and a massive vector field for the $J/ψ$ meson, we delve into the meson's spectral function and spin parameters $(λ_θ,\, λ_φ,\,λ_{θφ})$ for different cases, assessing their response to variations in magnetic field strength, momentum, and temperature. We initially examine scenarios where a meson's momentum aligns parallel to the magnetic field in helicity frame. Our results reveal a magnetic field-induced positive $λ_θ^\text{H}$ for low meson momentum, transitioning to negative with increased momentum. As a comparison, we also study the case of momentum perpendicular to the magnetic field and find the direction of magnetic field does not affect the qualitative behavior for the $eB$-dependence of $λ_θ^\text{H}$. Moreover, we apply our model to real heavy-ion collisions for three different spin quantization directions. Further comparisons with experimental data show qualitative agreement for spin parameters $λ_θ$ and $λ_φ$ in the helicity and Collins-Soper frames.

hep-ph↗

arXiv2024

Holographic spin alignment for vector mesons

We develop a general framework for studying the spin alignment $ρ_{00}$ for flavorless vector mesons by using the gauge/gravity duality. Focusing on the dilepton production through vector meson decay, we derive the relation between production rates at each spin channel and meson's spectral function, which can be evaluated by holographic models for a strongly coupled system. As examples, we study $ρ_{00}$ for $J/ψ$ and $ϕ$ mesons, induced by the relative motion to a thermal background, within the soft-wall model. We show that $ρ_{00}$ in the helicity frame for $J/ψ$ and $ϕ$ mesons have positive and negative deviations from 1/3 at $T=150$ MeV, respectively, which consequently leads to different properties for their global spin alignments.

hep-ph↗

arXiv2019

Topological band theory for non-Hermitian systems from the Dirac equation

We identify and investigate two classes of non-Hermitian systems, i.e., one resulting from Lorentz-symmetry violation (LSV) and the other from a complex mass (CM) with Lorentz invariance, from the perspective of quantum field theory. The mechanisms to break, and approaches to restore, the bulk-boundary correspondence in these two types of non-Hermitian systems are clarified. The non-Hermitian system with LSV shows a non-Hermitian skin effect, and its topological phase can be characterized by mapping it to the Hermitian system via a non-compact $U(1)$ gauge transformation. In contrast, there exists no non-Hermitian skin effect for the non-Hermitian system with CM. Moreover, the conventional bulk-boundary correspondence holds in this (CM) system. We also consider a general non-Hermitian system in the presence of both LSV and CM, and we generalize its bulk-boundary correspondence.

cond-mat.mes-hall↗