# Ultralight Vector Dark Matter from non-slowroll Inflation

- Institution: CERN
- Speaker: Martina La Rosa
- Year: 2026
- Language: English
- Source: [CERN](https://videos.cern.ch/record/3020980)
- Licence: [CERN](https://copyright.web.cern)
- Who can watch: Teens profiles and older (sources give no ratings; placed by Invisible Network from the source's own words)

The longitudinal mode of a massive vector field, generated during inflation, offers a well motivated and phenomenologically rich candidate for dark matter. We show that a rapid variation in the mass of the vector boson, occurring during a brief phase of non-slowroll inflationary evolution, can naturally give rise to extremely small vector masses after inflation ends, corresponding to an ultralight dark matter candidate, with masses as low as m ≃ 10^{−19} eV or even smaller. This represents a refined and self-contained production mechanism: it does not rely on additional assumptions beyond the inflationary dynamics itself and the presence of a massive field. It also predicts, as a probe, a stochastic gravitational-wave background, generated at second order by non-adiabatic longitudinal vector fluctuations. This constitutes a distinctive observational signature of our framework. By leveraging a brief departure from slowroll dynamics, this framework also establishes a novel connection between ultralight vector dark matter and primordial black hole physics, suggesting a possible unified setting for mixed dark matter scenarios.

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## Lectures

1. [Ultralight Vector Dark Matter from non-slowroll Inflation](https://invisiblenetwork.ai/learn/cern/3020980/bf28d8200dcd), 9 min (CERN's player)