relativity & standard model question

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QuantumTroll
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relativity & standard model question

Postby QuantumTroll » Tue Jun 26, 2007 8:46 pm UTC

I've got some (I think) difficult conceptual physics questions, some of which I've had for two years without an answer.

This first one is for all you physicist types with knowledge of general relativity and particle physics:

GR says gravity is the result of the "bending" of space-time due to massive objects. This has recently been confirmed to a very high accuracy by the Gravity Probe B experiment, not to mention gravitational lensing and all that.

The Standard Model paints a completely different picture. It claims that the Higgs boson is responsible for gravity, and the particles' interactions with a Higgs field is what gives them mass.

How do you reconcile these two views on gravity?

I'm inclined to view the Higgs particle as a quantized amount of "space-time curvature", but this sounds like meaningless jibjab... but I've never seriously touched quantum field theory, so I don't really have a clue.

Maniac
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Postby Maniac » Tue Jun 26, 2007 8:56 pm UTC

Well, my fist answer would be: the Higgs gives them mass, but only mass without any gravitation ...

Gravitation is something completly different and has nothing to do with the higgs ....

The_Spectre
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Postby The_Spectre » Wed Jun 27, 2007 1:12 am UTC

Maniac wrote:Well, my fist answer would be: the Higgs gives them mass, but only mass without any gravitation ...

Gravitation is something completly different and has nothing to do with the higgs ....

Yep, this is completely correct. The Standard Model does not include gravity in any way.

Reconciling the standard model with general relativity, which essentially involves finding a working theory of quantum gravity, is basically the holy grail of theoretical high-energy physics at the moment. It's a pretty deep problem. I doubt anyone here knows the answer, and if they do, they should go publish and pick up their Nobel prize. :)

shill
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Postby shill » Wed Jun 27, 2007 1:55 am UTC

All I know is that quantum gravity theories posit a particle called the graviton, a massless particle with spin 2.
Last edited by shill on Wed Jun 27, 2007 4:27 am UTC, edited 1 time in total.

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QuantumTroll
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Postby QuantumTroll » Wed Jun 27, 2007 2:48 am UTC

Thanks for the replies! So the Standard Model simply says nothing about gravity.

Then, what force does the Higgs boson mediate? Photon does EM, gluon does color, etc. Does the Higgs just make inertia, then? Would that be calling inertia a force? Man, you guys really confused me :(

I should probably do some reading before posting more and making a fool of myself, but I never was one for self-restraint on message boards...

If the Higgs has nothing to do with gravity, then why is gravitational mass and inertial mass the same? I'm guessing this is the Big Question nobody has an answer to. It just seems really obvious to me that the gravity and inertia must be linked if every particle has the same inertial mass as gravitational mass.

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Postby shill » Wed Jun 27, 2007 3:42 am UTC

I'm sorry I have to do this:

Image

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ArmonSore
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Postby ArmonSore » Wed Jun 27, 2007 4:04 am UTC

Somebody explained it something like this once:

With gravity we have a force that acts on all matter in exactly the same way. That means that there are no standards that we can place which are external to gravity.

For example, if an electric force will cause an electron to do something, but a neutron won't be affected at all. So we could use neutrons to give a standard of length external to electromagnetism.

But all things(even light) are affected by gravity. So there is no ruler that can be constructed that won't be warped by gravity. And because of this fact gravity lends itself to a model of warped spacetime. But it's no better than any other model that would describe the effects of gravity, and hence all are equivalent. Gravitons are just another way of looking at the same thing.
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archgoon
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Postby archgoon » Wed Jun 27, 2007 6:37 am UTC

Well, I happen to know someone who knows the resolution to the quantum gravity problem. He refuses to publish, though, because he's from the future, and insists it would cause a serious paradox. :)
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