I sort of understand, when hand held, the fact of Josephson junctions, and now I learn that some people discovered that if you increase the pressure on one side of a superconducting fluid across a gap (already in flow/jumping?-- I don’t understand) a measurable force will change and (for gyroscopes) is torqued by whatever spin.
Ok, I picture a water hose stepped on. Now, I understand, sort of, that the whole neatness is that the gap is a real gap, but not how its overcome by a phenomenon different than quantum tunneling (a subject of course I have mastered).
Single whistle at fluid at crazy low temperature. Whistle with different fluid at easier less crazy low temp too “low”–?–to monitor, so many monitors of…what?
Here and here (Wiki), in the context of its use in a quantum gyroscope usable for fine measurements on a “human” scale.
In the linked article they used helium-4 instead of helium-3 because it could achieve super conduction at an easier to reach temperature; making it far more practical.
I believe the big surprise was that rather than using one, much smaller hole than 70 nm, they just used thousands more. Something no one had tried, and certainly didn’t expect the fluid to reach a coherent, harmonic vibration with such an otherwise “noisy” and incoherent set-up.
As to how or why the fluid vibrates in some quantum state by moving over/across these holes, I have no clue.
No, the “easier because warmer” I understood, at face value at least. It was the “what” was too “low”–metaphor, I guess, for too low to hear, as in “lower the damn radio.”
Right. It creates an audible hum, not sure if it’s audible to the human ear or has to be amplified (I assume the latter). I imagine the pitch of this whistle is related to the rising or lowing in pressure of the system.
Any physical system which oscillates in some way can produce sound waves, or can be converted into sound waves one way or another, so long as your equipment is sensitive enough and calibrated correctly.
ETA: a regular blowing whistle has a little ball that vibrates inside the chamber due to air pressure. The sound then emanates from the slot or reed near the mouthpiece. Same idea on a molecular scale, I suppose.
I should clarify that the ball isn’t needed to create the tone, it adds chaotic variation to the pitch due to turbulence, making for a more noticeable trill. It’s the pressure in the chamber, flow of molecules and the way they resonate as they pass the opening as for how a whistle works.