对数非线性电动力学中的视界、零轨道与光子球相结构
Horizon, Null-Orbit, and Photon-Sphere Phase Structures in Logarithmic Nonlinear Electrodynamics
- Charmo University（查尔莫大学）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
该研究分析LNED中带电黑洞在参数空间中的三种相结构，揭示共享零半径边界但临界曲线不同，黑点保留光子球，非径向测地线形成亚稳态束缚态。
AI中文摘要：
我们在$(Q,\epsilon)$参数空间中研究LNED中静态、带电、渐近平坦的黑洞。我们区分三种相结构：视界几何、背景圆形零轨道以及有效光学几何的圆形光子轨道。它们共享一个零半径边界$Q_{\rm nc}(\epsilon;M)=\gamma M^{2/3}\epsilon^{1/6}$，但具有不同的临界结构：极值曲线$Q_{\rm ext}(\epsilon;M)$和合并曲线$Q_{\rm m}(\epsilon;M)$都终止于分岔点$(Q_{\rm b},\epsilon_{\rm b})$，其中$Q_{\rm b}=9M/[2\Gamma^2(1/4)]$，$\epsilon_{\rm b}=128\pi^2Q_{\rm b}^2$，而有效光子轨道合并曲线$Q_{\rm m}^{\rm ph}(\epsilon;M)$不经过该点。对于$\epsilon\ge\epsilon_{\rm b}$，接近$Q_{\rm nc}$会使视界缩小到零，并产生具有量子修正熵$S_{\eta}(r_{\rm h}\to0)=\eta$的黑点。它们的温度在分岔点处消失，对于$\epsilon>\epsilon_{\rm b}$则发散，除非$\eta\delta=1$。背景势$V_{\rm eff}^{\rm bg}(r)$在$r=0$处形成无限势垒，没有局部极值，充当完美排斥器。光子势$V_{\rm eff}^{\rm ph}(r)$被正则化，在有限半径处具有最大值，充当部分反射器。因此，黑点在有限半径处保留光子球。远离$Q_{\rm nc}$时，对于$\epsilon<\epsilon_{\rm b}$，两种几何在$Q_{\rm ext}$之上都支持无视界结构；对于$\epsilon\ge\epsilon_{\rm b}$，只有光学几何在$Q_{\rm nc}<Q<Q_{\rm m}^{\rm ph}$范围内支持这种结构。非径向测地线被阻挡在奇点之外，并可以形成亚稳态束缚态，而径向测地线要么到达$r=0$，要么逃逸到无穷远。临界碰撞参数编码了引力效应和光学几何效应，探测了不同的相结构。
英文摘要：
We investigate static, charged, asymptotically flat black holes in logarithmic nonlinear electrodynamics (LNED) within the $(Q,ε)$ parameter space. We distinguish three phase structures: the horizon geometry, the background circular null orbits, and the circular photon orbits of the effective optical geometry. All share a zero-radius boundary $Q_{nc}(ε;M)=γM^{2/3}ε^{1/6}$, but possess distinct critical structures: the extremal curve $Q_{ext}(ε;M)$ and the background merger curve $Q_{m}(ε;M)$ both terminate at the bifurcation point $(Q_{b},ε_{b})$, located at $r=0$. In contrast, the effective photon-orbit merger curve $Q_{m}^{ph}(ε;M)$ does not pass through this point. For $ε\geε_{b}$, approaching $Q_{nc}$ shrinks the horizon to zero radius, resulting in black points with non-zero, quantum-corrected entropy. Their Hawking temperature vanishes at the bifurcation point and diverges for $ε>ε_{b}$, except when $ηδ=1$, where the temperature at the bifurcation point also diverges. The background potential $V_{eff}^{bg}(r)$ develops an infinite barrier at $r=0$ without local extrema, acting as a perfect repeller. In contrast, the photon potential $V_{eff}^{ph}(r)$ is regularized with a maximum at a finite radius, acting as a partial reflector. Consequently, the black points retain photon spheres of finite radius. Away from $Q_{nc}$, for $ε<ε_{b}$, both geometries support horizonless structures above $Q_{ext}$; for $ε\geε_{b}$, only the optical geometry does so in the region $Q_{nc}<Q<Q_{m}^{ph}$. Non-radial geodesics are blocked from the singularity and can form metastable bound states, while radial geodesics either reach $r=0$ or escape to infinity. The critical impact parameter encodes both gravitational and optical-geometry effects, probing the distinct phase structures.
