# Construction and limitations of EFTs for hot QFT

- Institution: CERN
- Speaker: Philipp Schicho
- Year: 2026
- Language: English
- Source: [CERN](https://videos.cern.ch/record/3023663)
- 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)

Finite-temperature effective field theories (EFTs) were originally developed to study thermodynamics and phase transitions in non-Abelian gauge theories. More recently, they have experienced renewed interest as a tool for determining soft contributions to real-time lightcone observables.

In the context of cosmological phase transitions, the construction of such EFTs has reached new levels of automation. In particular, full dimension-six thermal hot EFTs have recently been constructed, including hot SMEFT. In this talk, I will discuss recent progress in building these EFTs, as well as their limitations. I will also briefly highlight alternative techniques, including the heat-kernel and Hilbert-series approaches at finite temperature.

Finally, I will discuss applications of these EFTs to cosmological phase transitions and outline both old and new strategies to systematically extend perturbative control beyond the high-temperature regime, enabling reliable descriptions across a wider range of temperatures.

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## Lectures

1. [Construction and limitations of EFTs for hot QFT](https://invisiblenetwork.ai/learn/cern/3023663/95cb838e460a), 1 h 6 min (CERN's player)