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(Big Think)   We haven't quite proven that gravity is quantum in nature, but experimentally revealing the gravitational Aharonov-Bohm effect is a really big deal   (bigthink.com) divider line
    More: Cool, Quantum mechanics, individual quanta, electric field, quantum particles, Electromagnetism, clever experiments, magnetic potential, Photon  
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811 clicks; posted to STEM » on 18 Jan 2022 at 2:41 PM (17 weeks ago)   |   Favorite    |   share:  Share on Twitter share via Email Share on Facebook



27 Comments     (+0 »)
View Voting Results: Smartest and Funniest
 
2022-01-18 2:19:51 PM  
Well written article
 
2022-01-18 2:48:28 PM  
Where is the "For Dummies" version?
 
2022-01-18 2:51:13 PM  
I got about a quarter way into it before my brain went BZZZZZZZZZZZpop!
 
2022-01-18 2:55:51 PM  
... it's all the same force that behaves differently at different size-scales

/ducks
 
2022-01-18 2:56:53 PM  
Sounds reasonable. We already know that gravity moves at the speed of light, so a quantum interaction fits right in. I am curious how they 'blocked' gravity while mimicking the double slit test.
 
2022-01-18 3:02:48 PM  

madgonad: Sounds reasonable. We already know that gravity moves at the speed of light, so a quantum interaction fits right in. I am curious how they 'blocked' gravity while mimicking the double slit test.


By using a carefully-balanced ring mass equidistant from the path of the particle, so the gravitational forces all cancelled out, but left a higher gravitational potential. A simple and elegant solution, actually.
 
2022-01-18 3:05:52 PM  

KiltedBastich: By using a carefully-balanced ring mass equidistant from the path of the particle, so the gravitational forces all cancelled out, but left a higher gravitational potential. A simple and elegant solution, actually.


Yeah. HOW? I could envision how you could pull this off at L3, but how did they do it here?
 
2022-01-18 3:06:14 PM  

Jack Sabbath: Where is the "For Dummies" version?



madgonad: Sounds reasonable. We already know that gravity moves at the speed of light, so a quantum interaction fits right in. I am curious how they 'blocked' gravity while mimicking the double slit test.


The TL;dr here is that they took two rubidium atoms, cooled them down near 0K (so quantum behavior can be distinguished from thermal noise) and entangled them (so their properties remain correlated for as long as the entanglement does), and then launched them in a tube with a weight on the top. They start in the same gravitational potential, but the one that goes higher experiences a different potential change since it comes closer to the weight. We can't remove gravity or block it, but we can change the local gradient of the field, aka the potential.  Since they started entangled and thus in phase with each other, they should have stayed that way. But they found a phase difference that very closely matched the predicted values IF gravity was quantized.
 
2022-01-18 3:17:13 PM  

AlgaeRancher: Well written article


The Science paper is also very well done.
 
2022-01-18 3:18:50 PM  

PirateKing: Jack Sabbath: Where is the "For Dummies" version?


madgonad: Sounds reasonable. We already know that gravity moves at the speed of light, so a quantum interaction fits right in. I am curious how they 'blocked' gravity while mimicking the double slit test.

The TL;dr here is that they took two rubidium atoms, cooled them down near 0K (so quantum behavior can be distinguished from thermal noise) and entangled them (so their properties remain correlated for as long as the entanglement does), and then launched them in a tube with a weight on the top. They start in the same gravitational potential, but the one that goes higher experiences a different potential change since it comes closer to the weight. We can't remove gravity or block it, but we can change the local gradient of the field, aka the potential.  Since they started entangled and thus in phase with each other, they should have stayed that way. But they found a phase difference that very closely matched the predicted values IF gravity was quantized.


Thanks.. I understand it a little better now.

My main question is, does this have anything to do with Ant-Man?
 
2022-01-18 3:27:03 PM  
 
2022-01-18 3:32:14 PM  

Jack Sabbath: PirateKing: Jack Sabbath: Where is the "For Dummies" version?


madgonad: Sounds reasonable. We already know that gravity moves at the speed of light, so a quantum interaction fits right in. I am curious how they 'blocked' gravity while mimicking the double slit test.

The TL;dr here is that they took two rubidium atoms, cooled them down near 0K (so quantum behavior can be distinguished from thermal noise) and entangled them (so their properties remain correlated for as long as the entanglement does), and then launched them in a tube with a weight on the top. They start in the same gravitational potential, but the one that goes higher experiences a different potential change since it comes closer to the weight. We can't remove gravity or block it, but we can change the local gradient of the field, aka the potential.  Since they started entangled and thus in phase with each other, they should have stayed that way. But they found a phase difference that very closely matched the predicted values IF gravity was quantized.

Thanks.. I understand it a little better now.

My main question is, does this have anything to do with Ant-Man?


No, but it is a pretty pimp article.
 
2022-01-18 3:43:07 PM  

PirateKing: We can't remove gravity or block it, but we can change the local gradient of the field, aka the potential.  Since they started entangled and thus in phase with each other, they should have stayed that way. But they found a phase difference that very closely matched the predicted values IF gravity was quantized.


As the article notes at the end (and which follows axiomatically from the headline that asks a question), this doesn't really require quantized gravity.  It just requires the interaction of quantum matter with a classical gravitational potential.
 
Juc [TotalFark]
2022-01-18 3:46:28 PM  
Any time they can explain the real nitty gritty of smaller and smaller events or things we don't have a full handle on, the better.

Hell if covid keeps going on I'm going to need some of those baron harkonen anti-grav fat holder-uppers.
 
2022-01-18 3:58:35 PM  

Concrete Donkey: https://www.sciencenews.org/article/quantum-particles-gravity-spacetime-aharonov-bohm-effect


Oh look. A far better written article


i.kym-cdn.comView Full Size
 
2022-01-18 4:14:21 PM  
What does it mean for gravity to move at the speed of light?
 
2022-01-18 4:36:57 PM  

gnosis301: What does it mean for gravity to move at the speed of light?


That it has zero (rest) mass.
 
2022-01-18 4:47:20 PM  

madgonad: KiltedBastich: By using a carefully-balanced ring mass equidistant from the path of the particle, so the gravitational forces all cancelled out, but left a higher gravitational potential. A simple and elegant solution, actually.

Yeah. HOW? I could envision how you could pull this off at L3, but how did they do it here?


By launching the atoms straight up in a tube with a heavy ring at the top. All the vectors are accounted for. As I said, the design is actually very simple. The hard part is being able to do it with sufficient precision.
 
2022-01-18 4:51:46 PM  

AlgaeRancher: Well written article



the UFO's sure seem to have gravity under control.
 
2022-01-18 4:52:28 PM  

gnosis301: What does it mean for gravity to move at the speed of light?


That gravitational effects propagate, and the speed at which they propagate is the speed of light.
 
2022-01-18 4:59:12 PM  

KiltedBastich: madgonad: KiltedBastich: By using a carefully-balanced ring mass equidistant from the path of the particle, so the gravitational forces all cancelled out, but left a higher gravitational potential. A simple and elegant solution, actually.

Yeah. HOW? I could envision how you could pull this off at L3, but how did they do it here?

By launching the atoms straight up in a tube with a heavy ring at the top. All the vectors are accounted for. As I said, the design is actually very simple. The hard part is being able to do it with sufficient precision.


Your last sentence is a superposition.  It is simultaneously the reason we have applied scientists and is the reason they go insane.
 
2022-01-18 5:03:11 PM  

gnosis301: What does it mean for gravity to move at the speed of light?


If you move a source of gravity (mass), it will alter the gravitational field around it. How long will it take for distant bodies to be affected by the change in gravity?
 
2022-01-18 5:04:03 PM  

dionysusaur: gnosis301: What does it mean for gravity to move at the speed of light?

That it has zero (rest) mass.


If you treat it as a quantized particle (the graviton). But you can still talk about a speed of gravity, such as in classical general relativity, without bringing quantum mechanics into it.
 
2022-01-18 5:27:34 PM  

gnosis301: What does it mean for gravity to move at the speed of light?


Everyone can c how fat you are.
 
2022-01-18 5:32:55 PM  

Hawk the Hawk: Your last sentence is a superposition.  It is simultaneously the reason we have applied scientists and is the reason they go insane.


Look it's sitting and doing equations all day that would make me lose it. Experiments are WAY more fun.

(.. especially the "Time to kludge shiat together from spare parts to approximate the measurement apparatus I need" step, I DELIGHT in that.)
 
2022-01-18 5:43:35 PM  

Felgraf: Hawk the Hawk: Your last sentence is a superposition.  It is simultaneously the reason we have applied scientists and is the reason they go insane.

Look it's sitting and doing equations all day that would make me lose it. Experiments are WAY more fun.

(.. especially the "Time to kludge shiat together from spare parts to approximate the measurement apparatus I need" step, I DELIGHT in that.)


Oh sure, sure, sure.  Sounds like this sort of behavior can affect your error budget.

Yeah, that's right, you're basically an error accountant!

(Lulz)
 
2022-01-18 7:13:30 PM  

Hawk the Hawk: Yeah, that's right, you're basically an error accountant!


Just like an engineer - what's my error band and how much are you willing to spend to get the performance inside it?
 
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