The Return of the Singularities: Applications of the Smeared Null Energy Condition

Null Energy Condition Violations in Eternal Inflation

The usual scenario of ``eternal inflation'' involves an approximately de Sitter spacetime undergoing upward fluctuations of the local expansion rate $H$. This spacetime requires frequent violations of the Null Energy Condition (NEC). We investigate the fluctuations of the energy-momentum tensor of the scalar field in de Sitter space as a possible source of such violations. We find that fluctuations of the energy-momentum tensor smeared in space and time are well-defined and may provide the NEC violations. Our results for slow-roll inflation are consistent with the standard calculations of infl…

A singularity theorem for evaporating black holes

The classical singularity theorems of General Relativity rely on energy conditions that are easily violated by quantum fields. Here, we provide motivation for an energy condition obeyed in semiclassical gravity: the smeared null energy condition (SNEC), a proposed bound on the weighted average of the null energy along a finite portion of a null geodesic. Using SNEC as an assumption we proceed to prove a singularity theorem. This theorem extends the Penrose singularity theorem to semiclassical gravity and has interesting applications to evaporating black holes.

宇宙能承受多少 NEC 破缺？

How Much NEC Breaking Can the Universe Endure?

本研究探讨了涂抹零能量条件对违反 NEC 的宇宙学的理论约束，推导出暗能量状态方程参数界限及反弹相持续时间与 Hubble 参数增长率的不等式，并验证了其与 DESI 近期约束的一致性。

非最小耦合、负零能量与有效场论

Non-minimal coupling, negative null energy, and effective field theory

本文将非最小耦合视为有效场论的一部分，证明平均零能量条件在经典与量子层面均成立，并建立依赖场值范围的抹平零能量条件，从而约束可穿越虫洞等奇异现象。

Conditional escape of gravitons from the brane

In this paper we consider a cosmological Friedmann Robertson Walker brane world imbedded in a 5-dimensional anti-de Sitter Schwarzschild bulk. We show, using potential diagrams, that for an anti-de Sitter bulk the null geodesics never return to the brane. Null geodesics do however return for k=+1 when we include the Schwarzschild like mass and the condition of return is obtained from the corresponding effective potential. We next obtain the condition for a gravitational signal to be emitted from a FRW brane with isotropically distributed matter. We use these results to investigate the conditio…

黑洞体锥奇点

Black hole bulk-cone singularities

本研究分析AdS施瓦西黑洞背景下热响应函数的奇点，推导绕黑洞体测地线对偶主导奇点的解析形式，发现其边界群速度超光速，强度由经典李雅普诺夫指数控制，为全息CFT中编码黑洞光子球提供普适特征。

利用引力解耦在最小几何形变无迹引力中研究可穿越虫洞

Traversable Wormholes in Minimally Geometrical Deformed Trace-Free Gravity using Gravitational Decoupling

本研究在无迹引力框架下用最小几何形变方法结合引力解耦，研究不同物态参数、引力源下的Morris-Thorne可穿越虫洞，发现零能量条件破缺并算出弱偏转角。

来自量子能量不等式对虫洞的限制

Wormhole restrictions from quantum energy inequalities

本文综述了量子能量不等式（QEIs）对半经典引力中可穿越虫洞构造的限制，考察了短虫洞和长虫洞解，并基于双重涂抹零能量条件给出了对 Maldacena-Milekhin-Popov 长虫洞的新约束。

代数量子动力学与SR选择

Algebraic quantum kinematics: Galilean covariance with positive energy confines unequal-time commutation to null sets

本文提出一个算子代数框架，将非相对论量子力学与狭义相对论联系起来，探讨了光子部分的实现、常数c和ħ的不同作用以及哈格-卡斯特勒网的结构障碍，提出了SR选择猜想。

球对称f(R)引力中的视界正则交叉聚焦与内视界障碍

Horizon-regular cross-focusing and inner-horizon obstructions in spherical f(R) gravity

本研究在球对称f(R)引力中构建视界正则双零判据，推导面积加权外向膨胀演化律，验证其在带电非恒定曲率黑洞中的有效性，明确柯西-视界陈述的适用条件。