# Curvature perturbation from first-order phase transitions & A positive-definite formulation of tunneling

- Institution: CERN
- Department: TH institutes
- Speaker: Ryusuke Jinno
- Year: 2025
- Language: English
- Source: [CERN](https://videos.cern.ch/record/3022246)
- Licence: [CERN](http://copyright.web.cern.ch)
- Who can watch: Teens profiles and older (sources give no ratings; placed by Invisible Network from the source's own words)

This talk is consists of two parts. In the first part I will talk about curvature perturbation produced in very strong first-order phase transitions. I will first explain super-hubble curvature perturbation based on 2311.16222, and then move on to hubble-scale curvature perturbation based on 2503.01962. In the second part I change the topic and talk about a new type of formulation of quantum tunneling that features positive-definite action based on an ongoing work..

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## Lectures

1. [Curvature perturbation from first-order phase transitions & A positive-definite formulation of tunneling](https://invisiblenetwork.ai/learn/cern/3022246/813dbdcbe465), 49 min (CERN's player)