[HN Gopher] Black Holes Shown to Act Like Quantum Particles
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       Black Holes Shown to Act Like Quantum Particles
        
       Author : theafh
       Score  : 22 points
       Date   : 2022-03-29 15:17 UTC (7 hours ago)
        
 (HTM) web link (www.quantamagazine.org)
 (TXT) w3m dump (www.quantamagazine.org)
        
       | westurner wrote:
       | From https://www.quantamagazine.org/massive-black-holes-shown-
       | to-... :
       | 
       | > _Physicists are using quantum math to understand what happens
       | when black holes collide. In a surprise, they've shown that a
       | single particle can describe a collision's entire gravitational
       | wave._
       | 
       | "Scale invariance in quantum field theory"
       | https://en.wikipedia.org/wiki/Scale_invariance#Scale_invaria...
        
       | BoiledCabbage wrote:
       | "The expectation is that quantum field theory does describe
       | classical physics," Roiban said. "It turns out that it is in this
       | way that it does it, by having zero uncertainty in some states."
       | 
       | > The upshot is that classical waves are easier to describe in
       | the language of quantum mechanics than researchers feared. "A
       | gravitational wave, or a wave of any kind, is something big and
       | floppy. It should depend on many little things," said Roiban. But
       | "once you know the collision plus one photon or one graviton in
       | the final state, then you know everything."
       | 
       | Isn't this essentially applying QFT in high gravity environments?
       | Something that's long been sought?
       | 
       | Am I missing something?
        
         | ravi-delia wrote:
         | It's not actually a quantum theory, just a quantum approach. We
         | use simplifying computational models for both black holes and
         | large (or high energy, or just weird) quantum systems, and
         | these researchers think they found success porting over some of
         | those techniques. We really, _really_ want spacetime to behave
         | like quantum fields do, but in general it just behaves
         | completely differently. In this particular instance though,
         | those differences don 't matter enough to make the tools of QFT
         | totally useless. Quantum physicists spend a lot of time
         | integrating lots and lots of tiny effects that may or may not
         | interact with each other in strange ways, which is handy
         | experience for working with colliding black holes. Or rather,
         | solving a subproblem coming from certain simplifying
         | techniques.
        
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       (page generated 2022-03-29 23:02 UTC)