Tootfinder

Two-point functions and the vacuum densities in the Casimir effect for the Proca field
A. A. Saharian, H. H. Asatryan
https://arxiv.org/abs/2507.07267 http…

Two-point functions and the vacuum densities in the Casimir effect for the Proca field
We investigate the properties of the vacuum state for the Proca field in the geometry of two parallel plates on background of (D+1)-dimensional Minkowski spacetime. The two-point functions for the vector potential and the field tensor are evaluated for higher-dimensional generalizations of the perfect magnetic conductor (PMC) and perfect electric conductor (PEC) boundary conditions. Explicit expressions are provided for the vacuum expectation values (VEVs) of the electric and magnetic field squ…

Black hole surrounded by perfect fluid dark matter with a background Kalb-Ramond field
Sohan Kumar Jha
https://arxiv.org/abs/2506.21911 https://

Black hole surrounded by perfect fluid dark matter with a background Kalb-Ramond field
With an intent to explore the interplay between the Lorentz symmetry breaking (LSB) and the presence of dark matter (DM), we obtain a static and spherically symmetric black hole (BH) solution in the background of nonminimally coupled Kalb-Ramond (KR) field surrounded by perfect fluid dark matter (PFDM). The KR field is frozen to a non-zero vacuum expectation value (VEV) that breaks the particle Lorentz symmetry spontaneously. We explore scalar invariants, Ricci Scalar, Ricci squared, and Kretsc…

Monsters are very real.
But they never emerge in a vacuum.
This piece by @… is nearly perfect in explaining why.
https://pluralistic.net/2025/07/19/sys

Exact plane symmetric black bounce with a perfect-fluid exterior obeying a linear equation of state
Hideki Maeda, Cristian Martinez
https://arxiv.org/abs/2506.14872

Exact plane symmetric black bounce with a perfect-fluid exterior obeying a linear equation of state
We investigate an exact two-parameter family of plane symmetric solutions admitting a hypersurface-orthogonal Killing vector in general relativity with a perfect fluid obeying a linear equation of state $p=χρ$ in $n(\ge 4)$ dimensions, obtained by Gamboa in 2012. The Gamboa solution is identical to the topological Schwarzschild-Tangherlini-(anti-)de~Sitter $Λ$-vacuum solution for $χ=-1$ and admits a non-degenerate Killing horizon only for $χ=-1$ and $χ\in[-1/3,0)$. We identify all possibl…

Weak null singularity for the Einstein-Euler system
Yuefeng Song
https://arxiv.org/abs/2506.16635 https://arxiv.org/pdf/2506.16635

Weak null singularity for the Einstein-Euler system
We study the behavior of a self-gravitating perfect relativistic fluid satisfying the Einstein-Euler system in the presence of a weak null terminal spacetime singularity. This type of singularities is expected in the interior of generic dynamical black holes. In the vacuum case, weak null singularities have been constructed locally by Luk, where the metrics extend continuously to the singularities while the Christoffel symbols fail to be square integrable in any neighborhood of any point on the…