arXiv subjects

Maximilian Koegler

Publications and source records attributed to Maximilian Koegler.

5 recordsLinked to original sources

arXiv2025

Weather Forecast for Vacuum Fluctuations in QED

We provide closed analytic expressions for the Uehling and Serber contributions of the vacuum fluctuations in QED using Meijer G-functions. Our work extends recently found results by offering a novel formulation for the Uehling and Serber potentials and explores their properties in more detail. The form of these potentials is analyzed, and their relevance for precision measurements in experiments is investigated. For the Uehling potential, we connect the solution with the propagation of photons through atmospheric turbulence.

hep-th↗

arXiv2024

Emerging entanglement on network histories

We show that quantum fields confined to Lorentzian histories of freely falling networks in Minkowski spacetime probe entanglement properties of vacuum fluctuations that extend unrestricted across spacetime regions. Albeit instantaneous field configurations are localized on one-dimensional edges, angular momentum emerges on these network histories and establish the celebrated area scaling of entanglement entropy.

hep-th↗

arXiv2022

Dark Matter Jets of Rotating Black Holes

We present a novel approach which produces Dark Matter jets along the rotation axis of Kerr black holes utilizing the Penrose process. The properties of these jets are investigated, as well as their potential to create Dark Matter overdensities in the solar system and in the vicinity of the black hole. We discover a highly collimated and long-range Dark Matter jet with a density that is most sensitive to the mass and distance to the black hole.

gr-qc↗

arXiv2021

Perturbative quantum consistency near black-hole horizon formation

We study the prelude to black-hole formation using a suspended shell composed of physical matter that fulfills the dominant energy condition. Here, the collapse of the shell is brought to rest when the formation of the horizon is imminent but has not yet occurred. As the main achievement of this work, we obtain the Feynman propagator which connects the interior and the exterior of the shell within two local coordinate patches. It is derived by drawing an analogy to the propagation of light across interfaces that separate regions with different susceptibilities inside a medium. As a first application, we use this propagator to determine the vacuum persistence amplitude in the presence of external sources. On timescales much shorter than the Page time, we find that the amplitude builds up with time yet remains consistent with perturbative unitarity.

hep-th↗

arXiv2020

Physics in precision-dependent normal neighborhoods

We introduce a procedure to determine the size and shape of normal neighborhoods in any spacetimes and their dependence on the precision of the measurements performed by arbitrary observers. As an example, we consider the Schwarzschild geometry in Riemann and Fermi normal coordinates and determine the size and shape of normal neighborhoods in the vicinity of the event horizon. Depending on the observers, normal neighborhoods extend to the event horizon and even beyond into the black hole interior. It is shown that the causal structure supported by normal neighborhoods across an event horizon is consistent with general relativity. In particular, normal neighborhoods reaching over an event horizon are void of the Schwarzschild coordinate singularity. In addition, we introduce a new variant of normal coordinates which we call Fermi normal coordinates around a point, unifying features of Riemann and Fermi normal coordinates, and analyze their neighborhoods.

gr-qc↗