- #246
sweetser
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The difference having answers makes...
Hello Carl:
In this forum, I am working on a rank 1 field theory to explain gravity as a gauge choice between changes in the potential and the connection (call it diffeomorphism invariance, which is also at the heart of GR, but the details of implementation are different). One consequence is that any rank 2 field theory for gravity will be superseded, included GR. If GEM is correct, the huge amounts of work on black holes and the singularities of GR is not relevant to the description of Nature. Ouch, that is not going to be popular! So for this forum, the first half of Prof. Motl's blog can be summarily dismissed.
EM theory is completely integrated with the standard model. There are 2 charges, and one massless force particle. It is reasonable to speculate that gravity, with only 1 charge and one massless force particle, should be a wee bit simpler to understand. The Newtonain law of gravity, and Coulomb's law are clones. Only for GEM, the relativistic forces also look similar. Here is the EM Lorentz force:
[tex]F_{EM}^{\mu}=q_e U_{\nu}(\nabla^{\mu} A^{\nu} - \nabla^{\nu} A^{\mu})[/tex]
A force is a coupling of the moving charge ([itex]q_e U_{\nu}[/itex]) with a field strength tensor ([itex]\nabla^{\mu} A^{\nu} - \nabla^{\nu} A^{\mu}[/itex]). Move a charge around in a field, forces happen. Right answers are simple and direct.
One path to GR is to start from Newton's law of gravity, which is flawed, and try to correct that one flaw, ignoring for example that no one tries to quantize Newtonian gravity. The result of that exercise is the field equations of GR. Gupta, Feynman, and Weinberg have all shown that to be the case.
If you start from a bad place, bad things follow. Instead, construct the GEM Lorentz force as happened in EM, as the charge in motion coupling to the field strength tensor:
[tex]F_{G}^{\mu}=-q_m U_{\nu}(\nabla^{\mu} A^{\nu} + \nabla^{\nu} A^{\mu}) [/tex]
I copied the EM equation, changed two signs, and swapped two labels. What could be more simple, and direct?
I see no value in his comments about Lagrangians, Hamiltonians, actions, and the Feynman integral approach because it is an all or nothing deal. If you know the right Lagrangian, you can calculate the Hamiltonian. If you know the right Lagrangian, you know the action. If you know the right Lagrangian, you know the Feynman integral which is the exponential of the action. If you first figure out one of the other three, then you can determine the set. They are a logically consistent set.
Prof. Motl like other researchers in gravity does not know one of these, therefore he does not know any of them. So this group flounders no matter what tool they use. It is kind of tragic really. The logic of physics is unkind.
Here is his best lip service:
Why is this lip service? There was a time when both Lubos and I posted to the newsgroup sci.physics.research. He was a strident believer in the value of string theory. I often found his position embarrassing even for other people doing string theory. I know my own lack of intellectual precision was embarassing to professionals reading SPR. Lubos conveyed the message that if you did not understand how right string theory was, you were foolish, or stupid but probably both. I had been listening to string theory - not studying it, just eavesdropping - and it did not make sense to me. The units for a volume of spacetime are just wrong, and if you get the units wrong, you are wrong. Compatification is a fancy name for bold physics BS. Call the stuff that stinks s--- and move on before the stench causes permanent brain damage.
There was a post in SPR years ago where someone said don't complain unless you have something better to offer. Once I reached the point of my unified field theory research where I had testable hypotheses (it is plural), I wrote Lubos, the poster child of string theory, a simple financial reward. If anyone anywhere in the world in the next ten years develops an explanation for gravity that uses more than 4 dimensions, then I would send $100 to Lubos. This was not a bet, there is no risk to Prof. Motl. I wrote out the check, but did not sign it, in April of 2004. I closed that bank account in 2006, so had to write another check. I sent Lubos the jpegs, along with a draft of my paper. No comments have been returned. So I have data that he is not interested in a complete set of equations in four dimensions that make predictions that challenge GR.
doug
Hello Carl:
In this forum, I am working on a rank 1 field theory to explain gravity as a gauge choice between changes in the potential and the connection (call it diffeomorphism invariance, which is also at the heart of GR, but the details of implementation are different). One consequence is that any rank 2 field theory for gravity will be superseded, included GR. If GEM is correct, the huge amounts of work on black holes and the singularities of GR is not relevant to the description of Nature. Ouch, that is not going to be popular! So for this forum, the first half of Prof. Motl's blog can be summarily dismissed.
EM theory is completely integrated with the standard model. There are 2 charges, and one massless force particle. It is reasonable to speculate that gravity, with only 1 charge and one massless force particle, should be a wee bit simpler to understand. The Newtonain law of gravity, and Coulomb's law are clones. Only for GEM, the relativistic forces also look similar. Here is the EM Lorentz force:
[tex]F_{EM}^{\mu}=q_e U_{\nu}(\nabla^{\mu} A^{\nu} - \nabla^{\nu} A^{\mu})[/tex]
A force is a coupling of the moving charge ([itex]q_e U_{\nu}[/itex]) with a field strength tensor ([itex]\nabla^{\mu} A^{\nu} - \nabla^{\nu} A^{\mu}[/itex]). Move a charge around in a field, forces happen. Right answers are simple and direct.
One path to GR is to start from Newton's law of gravity, which is flawed, and try to correct that one flaw, ignoring for example that no one tries to quantize Newtonian gravity. The result of that exercise is the field equations of GR. Gupta, Feynman, and Weinberg have all shown that to be the case.
If you start from a bad place, bad things follow. Instead, construct the GEM Lorentz force as happened in EM, as the charge in motion coupling to the field strength tensor:
[tex]F_{G}^{\mu}=-q_m U_{\nu}(\nabla^{\mu} A^{\nu} + \nabla^{\nu} A^{\mu}) [/tex]
I copied the EM equation, changed two signs, and swapped two labels. What could be more simple, and direct?
I see no value in his comments about Lagrangians, Hamiltonians, actions, and the Feynman integral approach because it is an all or nothing deal. If you know the right Lagrangian, you can calculate the Hamiltonian. If you know the right Lagrangian, you know the action. If you know the right Lagrangian, you know the Feynman integral which is the exponential of the action. If you first figure out one of the other three, then you can determine the set. They are a logically consistent set.
Prof. Motl like other researchers in gravity does not know one of these, therefore he does not know any of them. So this group flounders no matter what tool they use. It is kind of tragic really. The logic of physics is unkind.
Here is his best lip service:
That's exactly how "lucky" I feel.Motl said:Unless you're lucky to guess new physics with the complete equations directly, new physics can only be revealed by identifying new possible principles, constraints, or physical mechanisms.
Why is this lip service? There was a time when both Lubos and I posted to the newsgroup sci.physics.research. He was a strident believer in the value of string theory. I often found his position embarrassing even for other people doing string theory. I know my own lack of intellectual precision was embarassing to professionals reading SPR. Lubos conveyed the message that if you did not understand how right string theory was, you were foolish, or stupid but probably both. I had been listening to string theory - not studying it, just eavesdropping - and it did not make sense to me. The units for a volume of spacetime are just wrong, and if you get the units wrong, you are wrong. Compatification is a fancy name for bold physics BS. Call the stuff that stinks s--- and move on before the stench causes permanent brain damage.
There was a post in SPR years ago where someone said don't complain unless you have something better to offer. Once I reached the point of my unified field theory research where I had testable hypotheses (it is plural), I wrote Lubos, the poster child of string theory, a simple financial reward. If anyone anywhere in the world in the next ten years develops an explanation for gravity that uses more than 4 dimensions, then I would send $100 to Lubos. This was not a bet, there is no risk to Prof. Motl. I wrote out the check, but did not sign it, in April of 2004. I closed that bank account in 2006, so had to write another check. I sent Lubos the jpegs, along with a draft of my paper. No comments have been returned. So I have data that he is not interested in a complete set of equations in four dimensions that make predictions that challenge GR.
doug
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