New paper!

Non-perturbative methods for false vacuum decay
https://arxiv.org/abs/2104.10687 
with the amazing Eleanor Hall ( @quarkygirl) and Hitoshi Muruyama ( @sleptogenesis)

We propose a new (non-perturbative!) technique to calculate false vacuum decay rates. Important, because...

...accurate false vacuum decay calculations are needed to predict the resulting gravitational wave spectra.

I'll try to give a brief explanation below, but I also highly recommend Nell's excellent slides on the topic: https://bit.ly/3xc54Gt  at #DarkSectorRainbow last month...

...So, accurately calculating the gravitational wave spectrum from a first order phase transition is a big challenge.

Existing methods struggle particularly with strong coupling. Why?

The usual false vacuum decay formalism is well-defined for tree-level bounces, but...

...for radiatively induced phase-transitions, it needs modifications. A related issue is that an all-orders calculation of the effective action is manifestly convex.

What does that mean? A convex potential doesn't have more than one minimum -> no first order phase transition...

..."coarse-graining" in momentum scale is a useful solution. However, the accuracy of coarse graining usually depends on a large ratio of scales or a weak coupling.

We propose an alternative, where we enforce locality in field space (see fig) rather than in momentum space...

...that can be done in the language of the functional renormalization group, as we show.

Moreover, we work out a simple example, which we compare to the result found in other methods. As expected, the difference creep in at stronger coupling...

...We hope to develop this method further, and eventually study things like confinement / chiral symmetry breaking and the resulting gravitational wave spectra. I can't wait to learn more.

A big thank you to my wonderful collaborators! It has been an absolute joy

Oops, MurAyama, apologies!!