[troll science]: Unruh particle shower on a centrifuge

Submitted ⁨⁨3⁩ ⁨days⁩ ago⁩ by ⁨TauZero@mander.xyz⁩ to ⁨science_memes@mander.xyz⁩

https://mander.xyz/pictrs/image/ab35a238-90ae-4aae-959e-911d37574080.png

Unruh effect should work for any acceleration, including centripetal acceleration of a James Bond-style killer centrifuge/amusement ride. The “thermal bath” experienced by such an observer is composed mainly of photons, but also some elementary particles, in proportion to quantum field coupling strengths or something, coming in as a “particle shower” from the direction of the Rindler event horizon - namely down. The accelerated observer can capture these particles for use later. Did I get it all correct?

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ladicius@lemmy.world ⁨3⁩ ⁨days⁩ ago
I know some of these words.

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- whyNotSquirrel@sh.itjust.works ⁨3⁩ ⁨days⁩ ago
  can someone explain the joke to this person? I don’t have time.
  
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  - lime@feddit.nu ⁨2⁩ ⁨days⁩ ago
    the unruh effect is apparently a hypothetical situation where an accelerating body in a complete vacuum still encounters particles. i had no idea about this, sounds weird as hell.
    
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BB84@mander.xyz ⁨2⁩ ⁨days⁩ ago
good meme!

by the equivalence principle, even earth’s 1g gravitational field should already lead to some Unruh radiation for us, so you don’t even need a centrifuge!

but your centrifuge is interesting. from the PoV of someone at rest angular momentum needs to be conserved so as you get fatter the rotation must slow down as @herrpfad@feddit.org said. but from the troll’s PoV why should they slow down?? it’s a thermal spectrum, and acceleration is centrifugal, so why should there be a retrograde force?

i think the resolution is you don’t get exactly Unruh radiation (because your acceleration isn’t actually constant (its rotating)), but how exactly that affects the mode functions i have no idea

also let’s tag @surrealpartisan@lemmy.world

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- surrealpartisan@lemmy.world ⁨20⁩ ⁨hours⁩ ago
  Ooh, thanks for the tag! This is great!
  
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- TauZero@mander.xyz ⁨2⁩ ⁨days⁩ ago
  Another complication is that even if the centrifuge slows down as it gets heavier, you can recover most of that mechanical energy when you hop off the centrifuge with your now full jar. Then you can boost it back up almost up to full speed. So I’m not sure exactly at what point you input energy into the system to instantiate the particles. When they hit the belljar bottom transversely maybe? Is this some kind of Maxwell’s Demon situation where you need to close the jar before the particles fall back out?
  
  Also good to mention Earth! Logically, if Hawking radiation works for black holes it seems as if it would also work for any star or planet! But I’ve never seen this mentioned anywhere.
  
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  - BB84@mander.xyz ⁨1⁩ ⁨day⁩ ago
    So I did a bit more reading. It seems like acceleration alone is not enough for invoking equivalence principle and saying we have Unruh radiation. If it was enough, non-blackholes objects would Hawking radiate like both of us were suspecting. Apparently physicists are quite confident only blackholes can Hawking radiate.
    
    There is another picture that may work better for us. Instead of thinking of Unruh radiation (which would require doing serious QFT in curved spcetime calculations), we can think of the radiation coming from ripples popping up near the horizon (the black hole horizon for Hawking, the Rindler horizon for Unruh).
    
    In this picture you absolutely need a horizon to get radiation. So on the centrifuge you won’t feel any radiation 🤷‍♂️
    
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herrpfad@feddit.org ⁨3⁩ ⁨days⁩ ago
Unfortunately, the troll gets fatter with each eaten particle. Probably, that would decelerate him. Wouldn’t it?

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