
#127
Feb810, 01:20 AM

Sci Advisor
P: 5,307

They are essentially a "quantized metric field". There are some details like Ashtekars formulation, spin network states, induced ChernSimons gauge theory on the horizon, ... but essentially the spin network is what remains from GR 



#128
Feb810, 01:28 AM

Sci Advisor
P: 8,009





#129
Feb810, 01:40 AM

Sci Advisor
P: 5,307

I have to check Verlindes reasoning. I would say that there must be "something". Perhaps his approach is generic enough not to specify "something", but w/o "something" there would be nothing at all :)
I would say that Verlindes idea is to get rid of gravity as a fundamental entity b/c it always causes trouble. So perhaps his argument is viable with fundamental degrees of freedom (regradless what they are in detail), especially if the are not related to gravity. If you look at it from a particle physics perspective there are enough degrees of freedom to carry entropy. If you look at it from Smolins LQG perspecive it's clear that he needs gravity b/c w/o gravity LQG simply fades away:) 



#130
Feb810, 01:41 AM

P: 2,799

With objecting to rovelli I'm not suggesting that the original classical realist observer is the way, I am thinking of a different way but which is closer to the measurement ideal that is the idea of doing away with the observer. To me, it's not possible to do away with the observer. What one needs to define a measure of missing information, is distinguishable degrees of freedom. But if the distinguishable degrees of freedom are dependent on the observer, the constructed measure is intrinsically relative. I'm not saything there are no degrees of freedom. About Smolins ideas, he seems to have had more than one. Some of smolins reasoning (I'm thinking CNS and reality of time, evolution of law), are at least in my interpretation in stark contrast to rovelli's RQM ideas. Questions like why SU(2) are exactly the thinks that I think we could answer if we see it as an evolved equilibrium  rather than as a fixed eternal realist fact. I can't do this, but a possible pathway to doing it is at least visible to me. I think the symmetries, that more or less are the signatures of the SM might be explainable as selforganising memory structures interact and where the invariants are preferred during different conditions. This means that maybe these symmetries are not fundamental, in the observer indepedent way. I rather think that they are (at best) uniqely expected in the statistical sense for a very constrained class of observers. /Fredrik 



#131
Feb810, 01:46 AM

P: 2,799

About wigners friend, here is my simple reasoning of this.
For simplicity lets consider wigners friend to be somehow soldered onto the mesurement device, so that wigners friend and the apparatous are "one" :) Then we have two observers. Wigner and his friend/apparatous. The fact that wigner doesn't know what has happened (until he speaks to his friend) means his ACTION reflects this. This means we predict an interaction between wigner and his friend. Ultimately this interaction is canceled when they reach an agreement. This is an analogt but I mean this in a deeper sense, not just that wigner and his friend enter an intermittent argument, but that in a general example wigner and his friend could simply be system A and system B, both interacting with system C. The idea here, predicts that there is an interaction even between observers! /Fredrik 



#132
Feb810, 03:07 AM

P: 216

In 1968 Sakharov wrote the the gravity isn't a fundamental force and it is a secondary effect.
Marcus sent me a good link of 2010: http://arxiv.org/PS_cache/arxiv/pdf/...911.5004v2.pdf It is a long paper but it is good to read a summary. It seems for me that there isn't volume nor surface either. It is just a product of the information and a product seem to show an area. I prefer probability ρ(x) = ψ(x, t)*ψ(y, t) instead of ρ(x) = ψ [tex](x, t)^ 2[/tex] as in Copenhagen Interpretation. This product of the wave functions shows interesting properties: Tp / T(x) * Tp / T(y) = a Fg / Fe (lp / l x ) * (lp / l y ) = a Fg / Fe where Tp is a Planck time, lp is Planck length, lx, ly are Compton wave lengths , a (alfa) is fine structure const. Fg gravitational interaction, Fe electromagnetic interaction. In a computer the information creates a program of the image just in an interaction not in a define space. 



#133
Feb810, 03:11 AM

Sci Advisor
P: 5,307

Let's use an even simpler approach  "shut up and calculate".
We agree that every observer making measurements does not "see" the subsystem itself but only the 2dim. screen of the subsystem. I don't care how the observer itself is represented as he is located outside the subsystem :) 



#134
Feb810, 03:25 AM

P: 2,799

Although the 2dim screen defines the distinguishable events, further structure can emerge on the observer side of the screen as histories of events accumulate and organise. Maybe one can find an argument where certain representations are simply more likely to be preserved, and that these represtations have certain symmetries. This is the kind of first principle explanation of the symmetries I seek. So the inconsistencies of the observer bias, that cricits points out, are turned around and used as interactions that work as a selective pressure to evolve the observer. Then consider that even a particles can be thought of as an observers, one could understand the appearance of preferred particle hierarchies in this sense as expected "optimal representations" rather than "fundamental representations". /Fredrik 



#135
Feb810, 03:46 AM

P: 216





#136
Feb810, 10:43 AM

P: 216

A system is in an equilibrium if it absorbs and emits the same energy.
For example: A planet surface is a sphere and if we go deeper the subspheres are smaller proportionally to a squared distance from the surface. Therefore the entropy dS=Q/T might be balanced if the temperature T increases proportional to the squared distance from the surface according to dS=kA/4 [tex]L^2[/tex] A=area of the subsystem L= Planck length It seems strange how the systems with different temperature may be in thermal balance but it is in our Earth and we use it by pumping cold water into thermal deep hole and taking a warm water. 



#137
Feb1810, 02:18 PM

Sci Advisor
P: 1,136

A sort of coincidence but this role of the wave behavior in gravitational acceleration is now proved with a 10,000 fold improvement: better as one part in 100 million (7x109) Atom Interferometer Provides Most Precise Test Yet of Einstein's Gravitational Redshift http://www.sciencedaily.com/releases...0217131125.htm It's pure Mathematics: A wave packet in a potential field (which causes different frequencies at different places) will accelerate in the direction were the frequency is lower. This is just the same as the acceleration of a charged wave packet in an electric potential field (see my book Section 11.6 and shown in figure 11.4) EM Lorentz force derived from Klein Gordon's equation http://www.physicsquest.org/Book_Lo...ein_Gordon.pdf Regards, Hans 


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