发表机构
Dinabandhu Andrews Institute of Technology and Management（丁班杜·安德鲁斯科技管理学院）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文研究迷你玻色子星周围薄吸积盘，发现因无ISCO且比角动量趋零，标准内粘性力矩被自然淬灭，可作为区分黑洞与无地平线标量结构的新判据。
AI 中文摘要
标准Novikov-Thorne几何薄吸积盘模型假设在最内层稳定圆轨道（ISCO）处存在零力矩内边界条件。放宽这一假设以允许有限粘性力矩——由跨越内落区域的磁应力驱动——可以显著增强黑洞吸积流的辐射效率和高频光谱发射。虽然这一机制在Kerr时空中已得到充分确立，但其在无视界的奇异致密天体周围的热力学可行性在很大程度上仍未得到探索。在本文中，我们研究了内粘性力矩边界条件在嵌入规则迷你玻色子星时空中的薄盘中的应用。通过数值积分耦合的Einstein-Klein-Gordon场方程，并采用Lense-Thirring慢旋转近似，我们生成了一个严格满足弱能量条件的精确无视界背景。我们证明，坐标ISCO的拓扑缺失从根本上改变了吸积动力学。在没有突然测地线内落的情况下，稳定圆轨道深入致密标量核心，导致盘的物理内边界由开普勒角速度的峰值动态确定。由于流体比角动量在这个深层微观边界处趋近于零，标准粘性力矩在数学上被淬灭。因此，通常与黑洞中边界力矩相关的增强辐射通量发散在规则玻色子星周围自然被抑制。这种力矩淬灭提供了标准黑洞与无地平线超轻标量结构之间的一个稳健现象学判别器。
英文摘要
The standard Novikov-Thorne model for geometrically thin accretion disks assumes a zero-torque inner boundary condition at the innermost stable circular orbit (ISCO). Relaxing this assumption to allow a finite viscous torque---driven by magnetic stresses bridging the plunging region---can significantly enhance the radiative efficiency and high-frequency spectral emission of black hole accretion flows. While this mechanism is well-established for Kerr spacetimes, its thermodynamic viability around exotic, horizonless compact objects remains largely unexplored. In this article, we investigate the application of the inner viscous torque boundary condition to a thin disk embedded in a regular mini-boson star spacetime. By numerically integrating the coupled Einstein-Klein-Gordon field equations and employing the Lense-Thirring slow-rotation approximation, we generate an exact, horizonless background that strictly satisfies the weak energy condition. We demonstrate that the topological absence of a coordinate ISCO fundamentally alters the accretion dynamics. Without a sudden geodesic plunge, stable circular orbits penetrate deep into the dense scalar core, causing the physical inner boundary of the disk to be determined dynamically by the peak of the Keplerian angular velocity. Because the specific angular momentum of the fluid approaches zero at this deep microscopic boundary, the standard viscous torque is mathematically quenched. Consequently, the enhanced radiative flux divergence typically associated with boundary torques in black holes is naturally suppressed around regular boson stars. This torque quenching offers a robust phenomenological discriminator between standard black holes and horizonless ultralight scalar structures.
Comments10 pages, 3 figures
