10 papers
The End of the First Act: Spectral Running, Interacting Dark Radiation, and the Hubble Tension in Light of ACT DR6 Data
Mathias Garny, Florian Niedermann, Martin S. Sloth
We point out that constraints on reported by the ACT collaboration in their DR6 data release are surprisingly sensitive to the assumptions made about the initial…
Dark Acoustic Oscillations and the Hubble Tension
Mathias Garny, Florian Niedermann, Martin S. Sloth
The Hubble tension and the recently reported anomaly in data from the Dark Energy Spectroscopic Instrument (DESI) are considered to pose serious challenges to the standard CDM…
String-induced vacuum decay and its gravitational wave signatures
Aleksandr Chatrchyan, Florian Niedermann, Phoebe Richman-Taylor
False vacuum decay typically proceeds via the nucleation of spherical bubbles of true vacuum, described by symmetric field configurations in Euclidean time. In this work, we…
Axions, Three-Forms, and M-Theory
Florian Niedermann, Ziqi Yan
Scalar fields with masses protected by global shift symmetries, commonly referred to as axions, are abundantly used in effective field theories in cosmology and particle physics. H…
Dark Acoustic Oscillations as an Early-Universe Explanation of the DESI Anomaly
Mathias Garny, Florian Niedermann, Martin S. Sloth
DESI DR2 data have been widely interpreted as evidence for late-time evolving dark energy (DE) with an apparent phantom crossing. Here we investigate an alternative explanation, ba…
Hot New Early Dark Energy: Dark Radiation Matter Decoupling
Mathias Garny, Florian Niedermann, Henrique Rubira +1
We present a microscopic model of the dark sector that resolves the Hubble tension within standard current datasets based on well-known fundamental principles, gauge symmetry and s…