[pbhjpbhj]

Tangentially related:

When I was in uni, I did a brief informal undergrad-level paper on modelling cosmological inflation using superfluid He-4. What I hadn't realised, and perhaps was supposed to discover, was that one of the unis [past] professors, Prof JF Allen, had worked in that field. As I read now I find that he actually was a co-discoverer of superfluid He-4.

The journal Nature describes him as "the last of a generation of independent-minded classical physicists". We knew him as "god" for his mystical presence on campus and his cartoon-God appearance, whispers followed him around the physics lounge. He also taught me QFT, or tried. It wasn't until after I graduated that I learnt the building really was named after him. I do wish that I had known to interview him about this field of modelling [cosmology] using superfluids.

[OldGuyInTheClub]

Liquid helium 3 and 4 have been a fertile substrate for this kind of exploration. I often think that the lab scale experiments will figure it out before the ultracolliders.

This 1998 article summarizes the state of the field up to that time. The rotating cryostat they used in the experiments is a masterpiece of instrument design.

https://www.pnas.org/doi/pdf/10.1073/pnas.96.14.7760

"Vortices in rotating superfluid 3 He" by Lounasmaa and Thuneberg

Scroll to the end for

"Superfluid 3 He in Cosmology

The topological objects in the order parameter field of super- fluid 3 He, such as textural point defects, quantized vortex lines, and solitons, are in many respects similar to monopoles, strings, and domain walls in relativistic quantum field theories (3, 4, 23, 24). In high-energy physics these objects are still hypothetical, whereas in the case of superfluid 3 He they can be observed experimentally. Here we discuss just one example: an experiment modeling developments in the early universe. The study (67, 68) involves creation of vortices by absorption of neutrons in rotating superfluid 3 He-B."

[OldGuyInTheClub]

Addendum after the edit deadline: G.E. Volovik has an article on the theory behind this at

https://www.pnas.org/doi/epdf/10.1073/pnas.96.11.6042

"Field theory in superfluid 3He: What are the lessons for particle physics, gravity, and high-temperature superconductivity?"

I don't pretend to understand even a fraction of this but Figure 3 is a very nice Dictionary mapping the helium phenomena to the cosmological questions.

[at_a_remove]

Ah, I had the guy who was the master of Helium-3. He had something like seven patents on different applications.

[jacquesm]

I watched and posted a video about He-4, amazing example of what educational videos should look like. Thank you!