9 papers
Three Advanced Lectures on Inflation
Martin S. Sloth
Lecture notes on inflation. The lectures are three double lectures, held for the first time at the Nordita Winter School 2024 - Particle Physics and Cosmology, covering an advanced…
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…
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…
Soft gravitons as Goldstone modes of spontaneously broken asymptotic symmetries in de Sitter spacetimes
Martin S. Sloth
I demonstrate that soft graviton modes in de Sitter spacetimes are the Goldstone modes of the spontaneously broken asymptotic symmetry group of de Sitter space. I then show that an…
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…