This stuff isn't my strong suit at all, but I'm having a hard time grasping how sound waves can behave like subatomic particles in this way.
Pairs of sound waves pop in and out of existence in a laboratory vacuum, mimicking particle-antiparticle pairs in the vacuum of space.
Sound is a wave through some medium, so how can they pop into existence in a vacuum? Are particles of some kind (and what are they? Hydrogen atoms? Helium?) popping into existence long enough for them to physically interact with one another so a physical wave can propagate from one particle to another before they pop back out of existence, and thus "sound waves" are ap
by Anonymous Coward writes:
on Monday October 13, 2014 @11:04AM (#48130377)
"I'm having a hard time grasping how sound waves can behave like subatomic particles in this way."
It's done with phonons -- quantised fluctuations that in the classical limit are sound waves.
"Sound is a wave through some medium, so how can they pop into existence in a vacuum? Are particles of some kind (and what are they? Hydrogen atoms? Helium?) popping into existence long enough for them to physically interact with one another so a physical wave can propagate from one particle to another before they pop back out of existence, and thus "sound waves" are appearing?"
No, it's literally that pairs of phonons can be produced from the "sound vacuum" in the same way that pairs of photons can be produced in a normal vacuum. If you like, you can think of it as quantised shifts in the structure of the quantum fluid (superfluid helium or a Bose-Einstein condensate, or what have you) generating these phonons. It's not, strictly speaking, true but at least it's a physical picture.
"Seems the signal to noise ratio would be pretty bad."
I'm a long time out of this field -- I did my Masters in acoustic holes but that was a long time back -- but I'd also expect signal to noise to be pretty lousy. However, any signal at all would be awesome.
Sound waves as quantum particles? (Score:4, Interesting)
This stuff isn't my strong suit at all, but I'm having a hard time grasping how sound waves can behave like subatomic particles in this way.
Pairs of sound waves pop in and out of existence in a laboratory vacuum, mimicking particle-antiparticle pairs in the vacuum of space.
Sound is a wave through some medium, so how can they pop into existence in a vacuum? Are particles of some kind (and what are they? Hydrogen atoms? Helium?) popping into existence long enough for them to physically interact with one another so a physical wave can propagate from one particle to another before they pop back out of existence, and thus "sound waves" are ap
Re:Sound waves as quantum particles? (Score:5, Informative)
"I'm having a hard time grasping how sound waves can behave like subatomic particles in this way."
It's done with phonons -- quantised fluctuations that in the classical limit are sound waves.
"Sound is a wave through some medium, so how can they pop into existence in a vacuum? Are particles of some kind (and what are they? Hydrogen atoms? Helium?) popping into existence long enough for them to physically interact with one another so a physical wave can propagate from one particle to another before they pop back out of existence, and thus "sound waves" are appearing?"
No, it's literally that pairs of phonons can be produced from the "sound vacuum" in the same way that pairs of photons can be produced in a normal vacuum. If you like, you can think of it as quantised shifts in the structure of the quantum fluid (superfluid helium or a Bose-Einstein condensate, or what have you) generating these phonons. It's not, strictly speaking, true but at least it's a physical picture.
"Seems the signal to noise ratio would be pretty bad."
I'm a long time out of this field -- I did my Masters in acoustic holes but that was a long time back -- but I'd also expect signal to noise to be pretty lousy. However, any signal at all would be awesome.