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
for later
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.
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.
that's an implication of relativity, as opposed to a fact, correct?
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.
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.
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.
“The quantum”? Is there such a thing?
I'll bet that was a weighty tome.
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.
Aw, he just had a lot of pull with the professors.
Care to explain further? Or is the short version all you got?
Unification is a goal of Physics, obviously. But there aren’t that many (hundreds) of fundamental particles.
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.
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.
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.
I always thought they had magnets in their shoes.
Good explanation.
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