Our Cosmological Standard Model: Its Shortcomings and Ways Forward

by Florian Niedermann (NORDITA / SU)

Tuesday 29 Apr 2025, 13:15 → 14:15 Europe/Stockholm

FA32 (AlbaNova Main Building)

Thanks to our cosmological standard model, LambdaCDM, we have a remarkably detailed understanding of the evolution of the Universe from close to the Big Bang until today, nearly 14 billion years later. We are even confident enough to use the model to infer the initial conditions of the hot plasma that filled the Universe just fractions of a millisecond after the Big Bang. However, there are different observational and theoretical hints suggesting that a more refined model may be needed to describe the evolution of the Universe accurately. In this talk, I will focus on the so-called Hubble tension, arguably the strongest of these hints, and argue that if taken seriously, it could guide us toward a more fundamental understanding of the dark sector. In particular, I will make the case for a simple particle physics scenario where the latent heat released in a strong first-order phase transition changes the expansion history in the early Universe before the cosmic microwave background is formed.