Using fluids to model inaccessible realms of the cosmos(quantamagazine.org) |
Using fluids to model inaccessible realms of the cosmos(quantamagazine.org) |
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.
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."
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.
> But physicists seek the more fundamental, quantum theory of gravity that underlies Einstein’s picture; it’s this quantum gravity theory that governs extremes like the Big Bang and black holes. And one way to inch toward this complete theory is to study quantum fluctuations in the space-time fabric.
I'm uncomfortable with the implicit framing that quantum gravity is The One True Theory and we just need to figure out how to formalize it. I'm sure this comes from the author and not the researcher, maybe something was lost in translation from the technical to the colloquial, but nonetheless it is still inaccurate to say that there is any kind of certainty that this is the right path forward. (Ditto for dark matter and dark energy, though those could more accurately be described as lacks of models than models per se.)
[...]
"If the wave isn’t too tall, then this wave doesn’t interact with other waves of different frequencies — you can try this in the bathtub.
But if the amplitude gets high, then the different frequencies interact."
Fascinating!
https://www.youtube.com/watch?v=kOnoYQchHFw
"The Black Hole Machine"
Calculations provide predictions, experiments provide verification.
And if for some reason it doesn't work here, then that would be nice to know.
Besides, the experiments themselves are simulations.
I thought he was insulting me, but apparently I would have made a decent physicist.
Your professor also told you to take more physics, so he did in fact suggest you could be a decent physicist?
the real problem is that it moves very fast, so when I've tried jumping into this "wheel", I find it impossible to hold on on to it. I always fly out due to centrifugal forces
> Mullis has credited his use of LSD as integral to his development of PCR: "Would I have invented PCR if I hadn't taken LSD? I seriously doubt it. I could sit on a DNA molecule and watch the polymers go by. I learnt that partly on psychedelic drugs."[86]
https://en.m.wikipedia.org/wiki/Polymerase_chain_reaction#Hi...
cosmic wonders that leave me askew
they gobble up matter with voracious delight
sucking everything in, day or night
I am not affiliated with this blog in any way but find the arguments compelling: https://tritonstation.com/
Here's an interview with a researcher who is also trying to move beyond quantum formalisms for spacetime vis a vis gravity: https://www.quantamagazine.org/the-physicist-who-bets-that-g...
F1 teams for example constantly struggle getting their simulations to line up with their measurements.
Ideas are cheap and typically wrong. Proof is the only thing that matters. I am certain some human has already stated the right idea to unify QM and GR, but so what?
Turns out that centrifugal force "does exist" in side the rotating reference frame. As if, your looking down on the object rotating around a center, the only force there is centripetal pointing in and Inertia pointing tangent to the circle. However if you enter the reference frame of the object being flung around you lose the inertia term since your already the center of the system and then need a centrifugal term to make up for that.
So in reference to _being_ on a hamster wheel, the outward sensation could be attributed to a centrifugal apparent force.
So, I looked him up. If anything my biology teacher was being polite.
https://en.wikipedia.org/wiki/Kary_Mullis#Views_on_HIV/AIDS_...
https://alumni.berkeley.edu/california-magazine/winter-2019/...
EDIT: My opinion is that this is a case of a broken clock being right twice a day. The second article talks about his PCR breakthrough. It sounds like he was clever and lucky. But based on what else he seemed to have believed, I really don't think we should take his word on the LSD being the key.
On a separate note, I find your main argument not at all helpful to the current thread. Terrible people can create and do amazing things. But it's still an a good example.
EDIT: honestly, looking at the user's other comment doesn't fill me with confidence https://news.ycombinator.com/item?id=36756514
And I took a _lot_ of shrooms.
Unfortunately, I majored in Philosophy. So, I'll never find the right answer to life's great mysteries. I did get fairly good at pointing out the wrong ones, though.
Great! That's why it's fun to say.
I do find the prospect of scientists using a bit more amusing than the average employee, however, as the public expects them to be holy.
"You shouldn't have mentioned the stuff about Benzedrine. It's not that you got it wrong. It's just that I don't want kids who are thinking about going into mathematics to think that they have to take drugs to succeed."
-Paul Erdős responding to the author of a 1987 Atlantic Monthly article profiling his work (as well as his use of benzedrine).