3 ms·

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

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.

at_a_remove 3y ago
Ah, I had the guy who was the master of Helium-3. He had something like seven patents on different applications.
OldGuyInTheClub 3y ago
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 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 3y ago
  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 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.
jacquesm 3y ago
I watched and posted a video about He-4, amazing example of what educational videos should look like. Thank you!

at_a_remove 3y ago

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

OldGuyInTheClub 3y ago

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 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 3y ago
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 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.

jacquesm 3y ago

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