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From the 1 of 5 linked papers with an AI index.

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5 papers

astro-ph.GA2026

Superdiffusion at the Galactic Centre

Pau Amaro Seoane, Kostas Tzanavaris, Reinhard Genzel +14

The paper models the orbital evolution of the S‑star cluster around the Milky Way’s central black hole using a superdiffusive, fractional transport framework that accounts for long…

gr-qc2026

The free boundary problem in general relativity

Kostas Tzanavaris, Latham Boyle, Neil Turok

We study the action principle for space-times whose boundary is singular. We suggest that it is natural to treat the singularity as a {\it free} boundary, where the variation is un…

gr-qc2026

Perfect fluids revisited: an action principle approach

Kostas Tzanavaris

We revisit the variational principle for relativistic perfect fluids in a manifestly covariant formulation based on differential forms, with particular attention to the boundary da…

gr-qc2025

Popcorn EMRIs: Transient Gravitational Wave Signals and Their Analysis in Schwartz Space

Pau Amaro Seoane, Kostas Tzanavaris

We investigate extreme-mass ratio inspirals (EMRIs) with orbital periods exceeding the observational timescale of mHz gravitational wave observatories. In their early, highly eccen…

hep-th2025

Black Mirrors: CPT-Symmetric Alternatives to Black Holes

Kostas Tzanavaris, Latham Boyle, Neil Turok

Einstein's equations imply that a gravitationally collapsed object forms an event horizon. But what lies on the other side of this horizon? In this paper, we question the reality o…