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Experiments Show Gravity Is Not an Emergent Phenomenon
MIT Technology Review ^ | 08/24/2011 | Staff

Posted on 08/24/2011 2:52:57 PM PDT by Red Badger

The way gravity effects quantum particles proves that it cannot be an emergent phenomenon, says physicist.

One of the most exciting ideas in modern physics is that gravity is not a traditional force, like electromagnetic or nuclear forces. Instead, it is an emergent phenomenon that merely looks like a traditional force.

This approach has been championed by Erik Verlinde at the University of Amsterdam who put forward the idea in 2010. He suggested that gravity is merely a manifestation of entropy in the Universe, which always increases according to the second law of thermodynamics. This causes matter distribute itself in a way that maximises entropy. And the effect of this redistribution looks like a force which we call gravity.

Much of the excitement over Verlinde's idea is that it provides a way to reconcile the contradictions between gravity, which works on a large scale, and quantum mechanics, which works on a tiny scale.

The key idea is that gravity is essentially a statistical effect. As long as each particle is influenced by a statistically large number of other particles, gravity emerges. That's why it's a large-scale phenomenon.

But today, Archil Kobakhidze at The University of Melbourne in Australia points to a serious problem with this approach. He naturally asks how gravity can influence quantum particles.

Kobakhidze argues that since each quantum particle must be described by a large number of other particles, this leads to a particular equation that describes the effect of gravity.

But here's the thing: the conventional view of gravity leads to a different equation.

In other words, the emergent and traditional views of gravity make different predictions about the gravitational force a quantum particle ought to experience. And that opens the way for an experimental test.

As it happens, physicists have been measuring the force of gravity on neutrons for ten yeas or so. And...wait for the drum roll... the results exactly match the predictions of traditional gravitational theory, says Kobakhidze.

"Experiments on gravitational bound states of neutrons unambiguously disprove the entropic origin of gravitation," he says.

That's an impressive piece of physics. It'll be interesting to see how Verlinde and his supporters respond.

Ref: arxiv.org/abs/1108.4161: Once More: Gravity Is Not An Entropic Force


TOPICS: Culture/Society; Technical
KEYWORDS: electrogravitics; force; gravity; physics; unifiedtheory
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I've been saying this for years..........;^)
1 posted on 08/24/2011 2:53:03 PM PDT by Red Badger
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To: Red Badger

all I know is that life would be b-—tch without it.


2 posted on 08/24/2011 2:55:47 PM PDT by the invisib1e hand
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To: the invisib1e hand

Basically what they are saying is that gravity is not a ‘force’ it’s an ‘effect’.............


3 posted on 08/24/2011 2:56:52 PM PDT by Red Badger ("Treason doth never prosper.... What's the reason? Why if it prosper, none dare call it treason.")
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To: Red Badger
I thought were saying gravity is a force and the other guys were saying it's an effect. You know it's a force and I know it's a force but they didn't ask us.
4 posted on 08/24/2011 2:58:09 PM PDT by the invisib1e hand
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To: Red Badger

Gravity is certainly no friend of my emergent phenomenon.


5 posted on 08/24/2011 2:58:20 PM PDT by Fightin Whitey
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To: Red Badger

Even in the Garden of Eden which presumably was entropically regenerated from supernatural sources, something had to make sure that birds could fly but man and animals (and even that pesky serpent) remained firmly on the ground :-)


6 posted on 08/24/2011 3:00:42 PM PDT by HiTech RedNeck (There's gonna be a Redneck Revolution! (See my freep page) [rednecks come in many colors])
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To: Red Badger

This should be obvious to anyone.


7 posted on 08/24/2011 3:01:01 PM PDT by smokingfrog ( sleep with one eye open ( <o> ---)
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To: Red Badger

I wrote my thesis on this...1985....no big deal...


8 posted on 08/24/2011 3:05:43 PM PDT by Sacajaweau
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To: Red Badger
the effect of this redistribution looks like a force which we call gravity

Then May the Force Be With You

Hope I posted it before someone else....

9 posted on 08/24/2011 3:06:10 PM PDT by NorCoGOP (Obama's approval ratings: so low that Kenyans now accuse him of being born in the USA)
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To: Red Badger

>> Basically what they are saying is that gravity is not a ‘force’ it’s an ‘effect’.............

No, if I’m reading it correctly, there’s a camp that believes it’s an “effect” (emergent, not a traditional force) and a camp that holds that it’s a traditional force.

Each side has (different sets of) equations that describe how gravity ought to behave, but actual measurements of neutron gravity agree with what the “traditional force”
equations.

Therefore gravity IS a traditional force and NOT an emergent “effect”.


10 posted on 08/24/2011 3:06:18 PM PDT by Nervous Tick (Trust in God, but row away from the rocks!)
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To: Red Badger

me not understand :(


11 posted on 08/24/2011 3:06:37 PM PDT by MNDude (so that's what they meant by Carter's second term)
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To: Red Badger

I am surprised that Verlinde didn’t look into this himself. Oopz.


12 posted on 08/24/2011 3:08:15 PM PDT by Paradox (Obnoxious, Bumbling, Absurd, Maladroit, Assinine)
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To: the invisib1e hand

>> all I know is that life would be b-—tch without it.

Maybe so, but a little less of it on Moving Day would be cool. :-)


13 posted on 08/24/2011 3:09:01 PM PDT by Nervous Tick (Trust in God, but row away from the rocks!)
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To: Red Badger
Attributing gravity to quantum coherence or ergodic effects has never really been anything more than a quantum duck (quark! quark!).

We're stuck: that's all there is to it. Pretending we're not stuck by claiming gravity is an emergent phenomenon is not helpful.

14 posted on 08/24/2011 3:09:05 PM PDT by FredZarguna (The power of the greatest rock band of all time--now a crack legal team. Coming to ABC this fall!)
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To: Red Badger
This causes matter [to] distribute itself

Gravity has sentience? And will?

15 posted on 08/24/2011 3:10:50 PM PDT by newheart (When does policy become treason?)
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To: Red Badger

Hunh?

Title: Experiments Show Gravity Is Not an Emergent Phenomenon

From the article: Instead, it is an emergent phenomenon that merely looks like a traditional force.

Must be one of those spooky Quantum mechanical sentences.


16 posted on 08/24/2011 3:11:03 PM PDT by glorgau
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To: Nervous Tick

yeah. it’ll be great when there’s an iPhone app for that.


17 posted on 08/24/2011 3:11:15 PM PDT by the invisib1e hand
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To: Sacajaweau

You must have had an interesting Defense...


18 posted on 08/24/2011 3:11:23 PM PDT by FredZarguna (The power of the greatest rock band of all time--now a crack legal team. Coming to ABC this fall!)
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To: MNDude

>> me not understand :(

Don’t sweat it. Just rearrange the jargon into meaningful English sentences and no one will ever know. You might even get offered a postgraduate research grant!


19 posted on 08/24/2011 3:11:50 PM PDT by Nervous Tick (Trust in God, but row away from the rocks!)
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To: Red Badger
I thought for a while that gravity is an effect of time distorter do to the oscillating motion of matter (remember the faster you go time slows down)
20 posted on 08/24/2011 3:11:53 PM PDT by tophat9000 (American is Barack Oaken)
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for later


21 posted on 08/24/2011 3:12:31 PM PDT by Semper911 (When you want to rob Peter to pay Paul, you'll always have the support of Paul.)
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To: glorgau
It goes with this ENTIRE PARAGRPAH:

One of the most exciting ideas in modern physics is that gravity is not a traditional force, like electromagnetic or nuclear forces. Instead, it is an emergent phenomenon that merely looks like a traditional force.

22 posted on 08/24/2011 3:13:35 PM PDT by FredZarguna (The power of the greatest rock band of all time--now a crack legal team. Coming to ABC this fall!)
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To: Red Badger
I think it could be a little of both. Why couldn't the quantum, which is eveywhere and in everything, have enough mass, if evenly distributed, to hold things down? It would be sort of like living on a planet surrounded by undectable jello - an energy "aura".
I understand what Erik Verlinde is trying to say. From a quantum point of view, it makes sence. From a Neutonian point of view, it can't be put on film. (I can also see why these two fine fellows dissagree.)
23 posted on 08/24/2011 3:14:02 PM PDT by concerned about politics ("Get thee behind me, Liberal")
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To: Red Badger
Gravitas, on the other hand...


24 posted on 08/24/2011 3:14:11 PM PDT by SparkyBass
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To: tophat9000
remember the faster you go time slows down

When in relative motion near the speed of light, two observers each think that the other observer's clock runs slow. Neither observer believes his own clock to be running slower.

25 posted on 08/24/2011 3:16:13 PM PDT by FredZarguna (The power of the greatest rock band of all time--now a crack legal team. Coming to ABC this fall!)
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To: tophat9000
(remember the faster you go time slows down)

that's an implication of relativity, as opposed to a fact, correct?

26 posted on 08/24/2011 3:19:16 PM PDT by the invisib1e hand
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To: FredZarguna

I hope that when everyone has satisfied themselves how it works, this universe with its gravity and its hundreds of kinds of curious particles, they give a little thought to why it should be there at all and what it means. God may be a pointillist painter, but it makes no sense to ignore the entire picture.


27 posted on 08/24/2011 3:20:12 PM PDT by HiTech RedNeck (There's gonna be a Redneck Revolution! (See my freep page) [rednecks come in many colors])
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To: Red Badger

I have no idea what they are talking about but I did used to wonder how people on Star Trek always had plenty of gravity.

Of course it was probably no problem for Scotty.


28 posted on 08/24/2011 3:21:07 PM PDT by yarddog
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To: Red Badger

The idea that gravity comes about due to fundamental entropy arguments only created quite a stir on Slashdot when it first came out a year or so ago. Unlike the armwaving of cold fusion, this guy’s paper is on the net, and you can follow along provided you have enough math/physics to understand it.


29 posted on 08/24/2011 3:21:40 PM PDT by SpaceBar
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To: concerned about politics

“The quantum”? Is there such a thing?


30 posted on 08/24/2011 3:22:51 PM PDT by Williams (Honey Badger Don't Care)
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To: Sacajaweau
I wrote my thesis on this...1985....no big deal...

I'll bet that was a weighty tome.

31 posted on 08/24/2011 3:23:13 PM PDT by bigheadfred (But alas)
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To: yarddog

Maybe the floor was painted with dilithium paint at well under warp concentrations. The Enterprise never seemed to be plagued with outages to its gravity system.


32 posted on 08/24/2011 3:23:42 PM PDT by HiTech RedNeck (There's gonna be a Redneck Revolution! (See my freep page) [rednecks come in many colors])
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To: bigheadfred

Aw, he just had a lot of pull with the professors.


33 posted on 08/24/2011 3:24:37 PM PDT by HiTech RedNeck (There's gonna be a Redneck Revolution! (See my freep page) [rednecks come in many colors])
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To: Fightin Whitey
Gravity is certainly no friend of my emergent phenomenon.

Care to explain further? Or is the short version all you got?

34 posted on 08/24/2011 3:25:58 PM PDT by bigheadfred (But alas)
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To: HiTech RedNeck

Unification is a goal of Physics, obviously. But there aren’t that many (hundreds) of fundamental particles.


35 posted on 08/24/2011 3:27:16 PM PDT by FredZarguna (The power of the greatest rock band of all time--now a crack legal team. Coming to ABC this fall!)
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To: FredZarguna
When in relative motion near the speed of light, two observers each think that the other observer's clock runs slow. Neither observer believes his own clock to be running slower.

Which explains the holographic universe theory. Nothing is real until it is observed. Both parties saw their own reality. What they do with their own sense of reality determines the reality of all the others who come in contact with them. To each, their reality is real, and the other is in error.
The more people who believe one person or the other, the more the illusion becomes the reality to the masses. When they believe both, then time does slow down at the speed of light. Both pilots experienced the same thing, therefore, human conscience says time can be manipulated. It is now a human reality, because it is believed.

36 posted on 08/24/2011 3:28:51 PM PDT by concerned about politics ("Get thee behind me, Liberal")
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To: Williams

Maybe this is supposed to mean the existence of everything, at its smallest, in quantums? Like a wall or block made of woven beads that can’t individually be split?

I don’t grok stuff at this level very well, and I salute the scientists who have the minds suited to it.


37 posted on 08/24/2011 3:29:07 PM PDT by HiTech RedNeck (There's gonna be a Redneck Revolution! (See my freep page) [rednecks come in many colors])
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To: the invisib1e hand
What he is saying is not true.

However, an implication of relativity is a fact. The Special Theory of relativity is about as strongly enforced a law of Physics as any we have.

38 posted on 08/24/2011 3:29:46 PM PDT by FredZarguna (The power of the greatest rock band of all time--now a crack legal team. Coming to ABC this fall!)
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To: HiTech RedNeck

I always thought they had magnets in their shoes.


39 posted on 08/24/2011 3:30:15 PM PDT by yarddog
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To: Nervous Tick

Good explanation.


40 posted on 08/24/2011 3:30:41 PM PDT by Justa
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To: FredZarguna

At the most fundamental, no there aren’t that many. But isn’t it considered that any thing that is built up out of bosons is itself a boson? That would mean all the kinds of atoms that exist in nature as well as smaller things.


41 posted on 08/24/2011 3:32:19 PM PDT by HiTech RedNeck (There's gonna be a Redneck Revolution! (See my freep page) [rednecks come in many colors])
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To: HiTech RedNeck; Sacajaweau
Aw, he just had a lot of pull with the professors.

Maybe. They only said they wrote a thesis...

42 posted on 08/24/2011 3:33:21 PM PDT by bigheadfred (But alas)
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To: FredZarguna
Unification is a goal of Physics, obviously

So much so they made it a religion.

43 posted on 08/24/2011 3:36:51 PM PDT by bigheadfred (But alas)
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To: yarddog

I don’t remember if they had to always make sure that books, pencils, glasses containing beverages, etc. were tied down.


44 posted on 08/24/2011 3:37:39 PM PDT by HiTech RedNeck (There's gonna be a Redneck Revolution! (See my freep page) [rednecks come in many colors])
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To: Red Badger

Why is it that physicists can challenge conventional ‘consensus’ scientific theory, but climate scientists cannot?


45 posted on 08/24/2011 3:38:04 PM PDT by Lorianne
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To: Red Badger
As long as each particle is influenced by a statistically large number of other particles, gravity emerges.


46 posted on 08/24/2011 3:38:38 PM PDT by Errant
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To: bigheadfred

It’s easy to confuse a portrait with the Painter.


47 posted on 08/24/2011 3:40:19 PM PDT by HiTech RedNeck (There's gonna be a Redneck Revolution! (See my freep page) [rednecks come in many colors])
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To: Lorianne

You can argue theory. But not set in stone, verified, exemplified FACT.


48 posted on 08/24/2011 3:41:30 PM PDT by bigheadfred (But alas)
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To: Lorianne

Because nobody with a political axe to grind gives a shucky darn about exactly what makes gravity work the way it does?


49 posted on 08/24/2011 3:41:39 PM PDT by HiTech RedNeck (There's gonna be a Redneck Revolution! (See my freep page) [rednecks come in many colors])
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To: the invisib1e hand
that's an implication of relativity, as opposed to a fact, correct?

Correct

50 posted on 08/24/2011 3:42:11 PM PDT by tophat9000 (American is Barack Oaken)
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